Add optimization to TextureLayer

cc/layers/texture_layer.cc

 // Copyright 2010 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/layers/texture_layer.h"
 
 #include "cc/base/thread.h"
 #include "cc/layers/texture_layer_client.h"
 #include "cc/layers/texture_layer_impl.h"
 #include "cc/trees/layer_tree_host.h"
@@ skipping 65 matching lines @@
   else
     SetTextureId(0);
 }
 
 scoped_ptr<LayerImpl> TextureLayer::CreateLayerImpl(LayerTreeImpl* tree_impl) {
   return TextureLayerImpl::Create(tree_impl, id(), uses_mailbox_).
       PassAs<LayerImpl>();
 }
 
 void TextureLayer::SetFlipped(bool flipped) {
+  if (flipped_ == flipped)
+    return;
   flipped_ = flipped;
   SetNeedsCommit();
 }
 
 void TextureLayer::SetUV(gfx::PointF top_left, gfx::PointF bottom_right) {
+  if (uv_top_left_ == top_left && uv_bottom_right_ == bottom_right)
+    return;
   uv_top_left_ = top_left;
   uv_bottom_right_ = bottom_right;
   SetNeedsCommit();
 }
 
 void TextureLayer::SetVertexOpacity(float bottom_left,
                                     float top_left,
                                     float top_right,
                                     float bottom_right) {
   // Indexing according to the quad vertex generation:
   // 1--2
   // |  |
   // 0--3
+  if (vertex_opacity_[0] == bottom_left &&
+      vertex_opacity_[1] == top_left &&
+      vertex_opacity_[2] == top_right &&
+      vertex_opacity_[3] == bottom_right)
+    return;
   vertex_opacity_[0] = bottom_left;
   vertex_opacity_[1] = top_left;
   vertex_opacity_[2] = top_right;
   vertex_opacity_[3] = bottom_right;
   SetNeedsCommit();
 }
 
 void TextureLayer::SetPremultipliedAlpha(bool premultiplied_alpha) {
+  if (premultiplied_alpha_ == premultiplied_alpha)
+    return;
   premultiplied_alpha_ = premultiplied_alpha;
   SetNeedsCommit();
 }
 
 void TextureLayer::SetRateLimitContext(bool rate_limit) {
   if (!rate_limit && rate_limit_context_ && client_ && layer_tree_host())
     layer_tree_host()->StopRateLimiter(client_->Context3d());
 
   rate_limit_context_ = rate_limit;
 }
@@ skipping 92 matching lines @@
   // triple-buffered.  Single-buffered layers already prevent draws, so
   // can block too for simplicity.
   return DrawsContent();
 }
 
 bool TextureLayer::CanClipSelf() const {
   return true;
 }
 
 }  // namespace cc