rendering_helper - Warm up the rendering.

content/common/gpu/media/rendering_helper.cc

Index: content/common/gpu/media/rendering_helper.cc
diff --git a/content/common/gpu/media/rendering_helper.cc b/content/common/gpu/media/rendering_helper.cc
index 6693f5f07dd5a2cb2b983ea5d289d1a1dc7b835c..957ccd9d895820709a60001a73218ef55382434d 100644
--- a/content/common/gpu/media/rendering_helper.cc
+++ b/content/common/gpu/media/rendering_helper.cc
@@ -302,9 +302,36 @@ void RenderingHelper::Initialize(const RenderingHelperParams& params,
   glEnableVertexAttribArray(tc_location);
   glVertexAttribPointer(tc_location, 2, GL_FLOAT, GL_FALSE, 0, kTextureCoords);
 
+  if (frame_duration_ != base::TimeDelta())
+    WarmUpRendering(params.warm_up_iterations);
+
   done->Signal();
 }
 
+// The rendering for the first few frames is slow (e.g., 100ms on Peach Pit).
+// This affects the numbers measured in the performance test. We try to render
+// several frames here to warm up the rendering.
+void RenderingHelper::WarmUpRendering(int warm_up_iterations) {
+  unsigned int texture_id;
+  std::vector<GLubyte> emptyData(screen_size_.GetArea() * 2);

[piman, 2014/10/14 17:26:43]

nit: scoped_ptr<GLubyte[]> empty_data(new GLubyte[screen_size_.GetArea() * 2]);

std::vector doesn't guarantee contiguous storage (before c++11 STL, which we
don't use consistenly yet).

+  glGenTextures(1, &texture_id);
+  glBindTexture(GL_TEXTURE_2D, texture_id);
+  glTexImage2D(GL_TEXTURE_2D,
+               0,
+               GL_RGB,
+               screen_size_.width(),
+               screen_size_.height(),
+               0,
+               GL_RGB,
+               GL_UNSIGNED_SHORT_5_6_5,
+               &emptyData[0]);
+  for (int i = 0; i < warm_up_iterations; ++i) {
+    RenderTexture(GL_TEXTURE_2D, texture_id);
+    gl_surface_->SwapBuffers();
+  }
+  glDeleteTextures(1, &texture_id);
+}
+
 void RenderingHelper::UnInitialize(base::WaitableEvent* done) {
   CHECK_EQ(base::MessageLoop::current(), message_loop_);