FixedVector: Add "full" method.

Will be useful for an optimization to the Buffer Subject/Observer
pattern.

Also cleans up an ASSERT.

Bug: angleproject:2389
Bug: chromium:829906
Change-Id: I2f8313ab531bca61947a51cc2396c04fb5d4bb1d
Reviewed-on: https://chromium-review.googlesource.com/1002883
Reviewed-by: Luc Ferron <lucferron@chromium.org>
Reviewed-by: Lingfeng Yang <lfy@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>

Author: null77

src/common/FixedVector.h

@@ -80,6 +80,8 @@ class FixedVector final
     void resize(size_type count);
     void resize(size_type count, const value_type &value);
 
+    bool full() const;
+
   private:
     void assign_from_initializer_list(std::initializer_list<value_type> init);
 
@@ -245,15 +247,15 @@ void FixedVector<T, N, Storage>::clear()
 template <class T, size_t N, class Storage>
 void FixedVector<T, N, Storage>::push_back(const value_type &value)
 {
-    ASSERT(mSize + 1 <= N);
+    ASSERT(mSize < N);
     mStorage[mSize] = value;
     mSize++;
 }
 
 template <class T, size_t N, class Storage>
 void FixedVector<T, N, Storage>::push_back(value_type &&value)
 {
-    ASSERT(mSize + 1 <= N);
+    ASSERT(mSize < N);
     mStorage[mSize] = std::move(value);
     mSize++;
 }
@@ -318,6 +320,12 @@ void FixedVector<T, N, Storage>::assign_from_initializer_list(
         mSize++;
     }
 }
+
+template <class T, size_t N, class Storage>
+bool FixedVector<T, N, Storage>::full() const
+{
+    return (mSize == N);
+}
 }  // namespace angle
 
 #endif  // COMMON_FIXEDVECTOR_H_

src/common/FixedVector_unittest.cpp

@@ -134,4 +134,15 @@ TEST(FixedVector, Iteration)
     EXPECT_EQ(4, vistedCount);
 }
 
+// Test the "full" method.
+TEST(FixedVector, Full)
+{
+    FixedVector<int, 2> vec;
+
+    EXPECT_FALSE(vec.full());
+    vec.push_back(0);
+    EXPECT_FALSE(vec.full());
+    vec.push_back(1);
+    EXPECT_TRUE(vec.full());
+}
 }  // namespace angle