Add missing (and remove superfluous) 'explicit' from constructors.

cc/quad_culler_unittest.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/quad_culler.h"
 
 #include "cc/append_quads_data.h"
 #include "cc/layer_tiling_data.h"
 #include "cc/math_util.h"
 #include "cc/occlusion_tracker.h"
 #include "cc/overdraw_metrics.h"
 #include "cc/single_thread_proxy.h"
 #include "cc/test/fake_impl_proxy.h"
 #include "cc/test/fake_layer_tree_host_impl.h"
 #include "cc/tile_draw_quad.h"
 #include "cc/tiled_layer_impl.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/transform.h"
 
 namespace cc {
 namespace {
 
 class TestOcclusionTrackerImpl : public OcclusionTrackerImpl {
 public:
-    TestOcclusionTrackerImpl(const gfx::Rect& scissorRectInScreen, bool recordMetricsForFrame = true)
+    explicit TestOcclusionTrackerImpl(const gfx::Rect& scissorRectInScreen, bool recordMetricsForFrame = true)
         : OcclusionTrackerImpl(scissorRectInScreen, recordMetricsForFrame)
         , m_scissorRectInScreen(scissorRectInScreen)
     {
     }
 
 protected:
     virtual gfx::Rect layerScissorRectInTargetSurface(const LayerImpl* layer) const { return m_scissorRectInScreen; }
 
 private:
     gfx::Rect m_scissorRectInScreen;
@@ skipping 437 matching lines @@
     appendQuads(quadList, sharedStateList, childLayer.get(), it, occlusionTracker);
     appendQuads(quadList, sharedStateList, rootLayer.get(), it, occlusionTracker);
     EXPECT_EQ(quadList.size(), 9u);
     EXPECT_NEAR(occlusionTracker.overdrawMetrics().pixelsDrawnOpaque(), 0, 1);
     EXPECT_NEAR(occlusionTracker.overdrawMetrics().pixelsDrawnTranslucent(), 0, 1);
     EXPECT_NEAR(occlusionTracker.overdrawMetrics().pixelsCulledForDrawing(), 0, 1);
 }
 
 }  // namespace
 }  // namespace cc