feat: remove hard dependency on @angular/http

* Makes `@angular/http` an optional dependency since it is only being used by the icon module. An error will be thrown only if the user runs into something that requires the `HttpModule`.
* Moves the various icon error classes into `icon-errors.ts`.
* Moves the icon registry provider next to the registry itself, instead of in the same file as the icon directive.

Fixes angular#2616.

src/lib/icon/fake-svgs.ts

@@ -1,6 +1,4 @@
-import {
-  Response,
-  ResponseOptions} from '@angular/http';
+import {Response, ResponseOptions} from '@angular/http';
 
 /**
  * Fake URLs and associated SVG documents used by tests.

src/lib/icon/icon-errors.ts

@@ -0,0 +1,43 @@
+import {MdError} from '../core';
+
+/**
+ * Exception thrown when attempting to load an icon with a name that cannot be found.
+ * @docs-private
+ */
+export class MdIconNameNotFoundError extends MdError {
+  constructor(iconName: string) {
+    super(`Unable to find icon with the name "${iconName}"`);
+  }
+}
+
+/**
+ * Exception thrown when attempting to load SVG content that does not contain the expected
+ * <svg> tag.
+ * @docs-private
+ */
+export class MdIconSvgTagNotFoundError extends MdError {
+  constructor() {
+    super('<svg> tag not found');
+  }
+}
+
+/**
+ * Exception thrown when the consumer attempts to use `<md-icon>` without including @angular/http.
+ * @docs-private
+ */
+export class MdIconNoHttpProviderError extends MdError {
+  constructor() {
+    super('Could not find Http provider for use with Angular Material icons. ' +
+          'Please include the HttpModule from @angular/http in your app imports.');
+  }
+}
+
+/**
+ * Exception thrown when an invalid icon name is passed to an md-icon component.
+ * @docs-private
+ */
+export class MdIconInvalidNameError extends MdError {
+  constructor(iconName: string) {
+    super(`Invalid icon name: "${iconName}"`);
+  }
+}

src/lib/icon/icon-registry.ts

@@ -1,8 +1,12 @@
-import {Injectable, SecurityContext} from '@angular/core';
+import {Injectable, SecurityContext, Optional, SkipSelf} from '@angular/core';
 import {SafeResourceUrl, DomSanitizer} from '@angular/platform-browser';
 import {Http} from '@angular/http';
-import {MdError} from '../core';
 import {Observable} from 'rxjs/Observable';
+import {
+  MdIconNameNotFoundError,
+  MdIconSvgTagNotFoundError,
+  MdIconNoHttpProviderError,
+} from './icon-errors';
 import 'rxjs/add/observable/forkJoin';
 import 'rxjs/add/observable/of';
 import 'rxjs/add/operator/map';
@@ -14,27 +18,6 @@ import 'rxjs/add/operator/catch';
 import 'rxjs/add/observable/throw';
 
 
-/**
- * Exception thrown when attempting to load an icon with a name that cannot be found.
- * @docs-private
- */
-export class MdIconNameNotFoundError extends MdError {
-  constructor(iconName: string) {
-    super(`Unable to find icon with the name "${iconName}"`);
-  }
-}
-
-/**
- * Exception thrown when attempting to load SVG content that does not contain the expected
- * <svg> tag.
- * @docs-private
- */
-export class MdIconSvgTagNotFoundError extends MdError {
-  constructor() {
-    super('<svg> tag not found');
-  }
-}
-
 /**
  * Configuration for an icon, including the URL and possibly the cached SVG element.
  * @docs-private
@@ -44,9 +27,6 @@ class SvgIconConfig {
   constructor(public url: SafeResourceUrl) { }
 }
 
-/** Returns the cache key to use for an icon namespace and name. */
-const iconKey = (namespace: string, name: string) => namespace + ':' + name;
-
 /**
  * Service to register and display icons used by the <md-icon> component.
  * - Registers icon URLs by namespace and name.
@@ -83,7 +63,7 @@ export class MdIconRegistry {
    */
   private _defaultFontSetClass = 'material-icons';
 
-  constructor(private _http: Http, private _sanitizer: DomSanitizer) {}
+  constructor(@Optional() private _http: Http, private _sanitizer: DomSanitizer) {}
 
   /**
    * Registers an icon by URL in the default namespace.
@@ -386,7 +366,11 @@ export class MdIconRegistry {
    * cached, so future calls with the same URL may not cause another HTTP request.
    */
   private _fetchUrl(safeUrl: SafeResourceUrl): Observable<string> {
-    let url = this._sanitizer.sanitize(SecurityContext.RESOURCE_URL, safeUrl);
+    if (!this._http) {
+      throw new MdIconNoHttpProviderError();
+    }
+
+    const url = this._sanitizer.sanitize(SecurityContext.RESOURCE_URL, safeUrl);
 
     // Store in-progress fetches to avoid sending a duplicate request for a URL when there is
     // already a request in progress for that URL. It's necessary to call share() on the
@@ -408,8 +392,24 @@ export class MdIconRegistry {
   }
 }
 
+export function ICON_REGISTRY_PROVIDER_FACTORY(
+    parentRegistry: MdIconRegistry, http: Http, sanitizer: DomSanitizer) {
+  return parentRegistry || new MdIconRegistry(http, sanitizer);
+}
+
+export const ICON_REGISTRY_PROVIDER = {
+  // If there is already an MdIconRegistry available, use that. Otherwise, provide a new one.
+  provide: MdIconRegistry,
+  deps: [[new Optional(), new SkipSelf(), MdIconRegistry], [new Optional(), Http], DomSanitizer],
+  useFactory: ICON_REGISTRY_PROVIDER_FACTORY
+};
 
 /** Clones an SVGElement while preserving type information. */
 function cloneSvg(svg: SVGElement): SVGElement {
   return svg.cloneNode(true) as SVGElement;
 }
+
+/** Returns the cache key to use for an icon namespace and name. */
+function iconKey(namespace: string, name: string) {
+  return namespace + ':' + name;
+}

src/lib/icon/icon.spec.ts

@@ -1,10 +1,11 @@
 import {inject, async, TestBed} from '@angular/core/testing';
 import {SafeResourceUrl, DomSanitizer} from '@angular/platform-browser';
-import {XHRBackend} from '@angular/http';
+import {HttpModule, XHRBackend} from '@angular/http';
 import {MockBackend} from '@angular/http/testing';
 import {Component} from '@angular/core';
 import {MdIconModule} from './index';
 import {MdIconRegistry} from './icon-registry';
+import {MdIconNoHttpProviderError} from './icon-errors';
 import {getFakeSvgHttpResponse} from './fake-svgs';
 
 
@@ -36,7 +37,7 @@ describe('MdIcon', () => {
 
   beforeEach(async(() => {
     TestBed.configureTestingModule({
-      imports: [MdIconModule],
+      imports: [HttpModule, MdIconModule],
       declarations: [
         MdIconColorTestApp,
         MdIconLigatureTestApp,
@@ -394,6 +395,37 @@ describe('MdIcon', () => {
 });
 
 
+describe('MdIcon without HttpModule', () => {
+  let mdIconRegistry: MdIconRegistry;
+  let sanitizer: DomSanitizer;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      imports: [MdIconModule.forRoot()],
+      declarations: [MdIconFromSvgNameTestApp],
+    });
+
+    TestBed.compileComponents();
+  }));
+
+  beforeEach(inject([MdIconRegistry, DomSanitizer], (mir: MdIconRegistry, ds: DomSanitizer) => {
+    mdIconRegistry = mir;
+    sanitizer = ds;
+  }));
+
+  it('should throw an error when trying to load a remote icon', async() => {
+    expect(() => {
+      mdIconRegistry.addSvgIcon('fido', sanitizer.bypassSecurityTrustResourceUrl('dog.svg'));
+
+      let fixture = TestBed.createComponent(MdIconFromSvgNameTestApp);
+
+      fixture.componentInstance.iconName = 'fido';
+      fixture.detectChanges();
+    }).toThrowError(MdIconNoHttpProviderError);
+  });
+});
+
+
 /** Test components that contain an MdIcon. */
 @Component({template: `<md-icon>{{iconName}}</md-icon>`})
 class MdIconLigatureTestApp {

src/lib/icon/icon.ts

@@ -9,20 +9,10 @@ import {
   SimpleChange,
   ViewEncapsulation,
   AfterViewChecked,
-  Optional,
-  SkipSelf,
 } from '@angular/core';
-import {Http} from '@angular/http';
-import {DomSanitizer} from '@angular/platform-browser';
-import {MdError} from '../core';
-import {MdIconRegistry, MdIconNameNotFoundError} from './icon-registry';
+import {MdIconRegistry} from './icon-registry';
+import {MdIconNameNotFoundError, MdIconInvalidNameError} from './icon-errors';
 
-/** Exception thrown when an invalid icon name is passed to an md-icon component. */
-export class MdIconInvalidNameError extends MdError {
-  constructor(iconName: string) {
-      super(`Invalid icon name: "${iconName}"`);
-  }
-}
 
 /**
  * Component to display an icon. It can be used in the following ways:
@@ -250,15 +240,3 @@ export class MdIcon implements OnChanges, OnInit, AfterViewChecked {
     }
   }
 }
-
-export function ICON_REGISTRY_PROVIDER_FACTORY(
-    parentRegistry: MdIconRegistry, http: Http, sanitizer: DomSanitizer) {
-  return parentRegistry || new MdIconRegistry(http, sanitizer);
-}
-
-export const ICON_REGISTRY_PROVIDER = {
-  // If there is already an MdIconRegistry available, use that. Otherwise, provide a new one.
-  provide: MdIconRegistry,
-  deps: [[new Optional(), new SkipSelf(), MdIconRegistry], Http, DomSanitizer],
-  useFactory: ICON_REGISTRY_PROVIDER_FACTORY,
-};

src/lib/icon/index.ts

@@ -1,11 +1,11 @@
 import {NgModule} from '@angular/core';
-import {HttpModule} from '@angular/http';
 import {MdCommonModule} from '../core';
-import {MdIcon, ICON_REGISTRY_PROVIDER} from './icon';
+import {MdIcon} from './icon';
+import {ICON_REGISTRY_PROVIDER} from './icon-registry';
 
 
 @NgModule({
-  imports: [HttpModule, MdCommonModule],
+  imports: [MdCommonModule],
   exports: [MdIcon, MdCommonModule],
   declarations: [MdIcon],
   providers: [ICON_REGISTRY_PROVIDER],
@@ -14,4 +14,5 @@ export class MdIconModule {}
 
 
 export * from './icon';
-export {MdIconRegistry} from './icon-registry';
+export * from './icon-errors';
+export * from './icon-registry';

src/lib/package.json

@@ -23,7 +23,6 @@
   "homepage": "https://github.com/angular/material2#readme",
   "peerDependencies": {
     "@angular/core": "^4.0.0",
-    "@angular/common": "^4.0.0",
-    "@angular/http": "^4.0.0"
+    "@angular/common": "^4.0.0"
   }
 }