cc: Fix races in LTHDelegatedTest

cc/trees/layer_tree_host_unittest_delegated.cc

Index: cc/trees/layer_tree_host_unittest_delegated.cc
diff --git a/cc/trees/layer_tree_host_unittest_delegated.cc b/cc/trees/layer_tree_host_unittest_delegated.cc
index a504b2f60bbd62cec54cfa38857ca2c458f2c1fd..5267bbd956a7f88e6b74b750ae38b5b1e367ee78 100644
--- a/cc/trees/layer_tree_host_unittest_delegated.cc
+++ b/cc/trees/layer_tree_host_unittest_delegated.cc
@@ -471,8 +471,7 @@ class LayerTreeHostDelegatedTestLayerUsesFrameDamage
     : public LayerTreeHostDelegatedTestCaseSingleDelegatedLayer {
  public:
   LayerTreeHostDelegatedTestLayerUsesFrameDamage()

[danakj, 2015/01/05 19:45:14]

nit: you can just remove this whole constructor i think?

[sohanjg, 2015/01/06 07:25:22]

Done.

-      : LayerTreeHostDelegatedTestCaseSingleDelegatedLayer(),
-        first_draw_for_source_frame_(true) {}
+      : LayerTreeHostDelegatedTestCaseSingleDelegatedLayer() {}
 
   void DidCommit() override {
     int next_source_frame_number = layer_tree_host()->source_frame_number();
@@ -581,7 +580,6 @@ class LayerTreeHostDelegatedTestLayerUsesFrameDamage
             CreateFrameData(gfx::Rect(0, 0, 10, 10), gfx::Rect(3, 3, 1, 1)));
         break;
     }
-    first_draw_for_source_frame_ = true;
   }
 
   DrawResult PrepareToDrawOnThread(LayerTreeHostImpl* host_impl,
@@ -589,9 +587,6 @@ class LayerTreeHostDelegatedTestLayerUsesFrameDamage
                                    DrawResult draw_result) override {
     EXPECT_EQ(DRAW_SUCCESS, draw_result);
 
-    if (!first_draw_for_source_frame_)
-      return draw_result;
-

[sohanjg, 2015/01/05 12:39:58]

I think we can assume, PrepareToDraw will happen only after we have committed.
Isnt it ?

[danakj, 2015/01/05 19:45:14]

Yes but this is trying to prevent multiple draws from the same source frame from
being tested against, as followup frames would not have the same damage.

That said, I don't see anything in this test that would cause multiple draws per
source frame, so maybe this was just being overly cautious.

[sohanjg, 2015/01/06 07:25:22]

Acknowledged.

     gfx::Rect damage_rect;
     if (!frame->has_no_damage) {
       damage_rect = frame->render_passes.back()->damage_rect;
@@ -669,7 +664,6 @@ class LayerTreeHostDelegatedTestLayerUsesFrameDamage
 
  protected:
   scoped_refptr<DelegatedRendererLayer> delegated_copy_;
-  bool first_draw_for_source_frame_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostDelegatedTestLayerUsesFrameDamage);