mac: Improve framerate on accelerated pages in HiDPI mode.

content/browser/renderer_host/compositing_iosurface_mac.mm

 // Copyright (c) 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 "content/browser/renderer_host/compositing_iosurface_mac.h"
 
 #include <OpenGL/OpenGL.h>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 202 matching lines @@
   TRACE_EVENT1("browser", "CompositingIOSurfaceMac::DrawIOSurface",
                "has_io_surface", has_io_surface);
 
   [glContext_ setView:view];
   gfx::Size window_size(NSSizeToCGSize([view frame].size));
   gfx::Size pixel_window_size = window_size.Scale(scale_factor);
   glViewport(0, 0, pixel_window_size.width(), pixel_window_size.height());
 
   // TODO: After a resolution change, the DPI-ness of the view and the
   // IOSurface might not be in sync.
-  gfx::Size io_surface_size = pixel_io_surface_size_;
-  io_surface_size = pixel_io_surface_size_.Scale(1.0 / scale_factor);
-  quad_.set_size(io_surface_size, pixel_io_surface_size_);
+  io_surface_size_ = pixel_io_surface_size_.Scale(1.0 / scale_factor);
+  quad_.set_size(io_surface_size_, pixel_io_surface_size_);
 
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
 
   // Note that the projection keeps things in view units, so the use of
-  // window_size / io_surface_size (as opposed to the pixel_ variants) below is
+  // window_size / io_surface_size_ (as opposed to the pixel_ variants) below is
   // correct.
   glOrtho(0, window_size.width(), window_size.height(), 0, -1, 1);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
 
   glDisable(GL_DEPTH_TEST);
   glDisable(GL_BLEND);
 
   if (has_io_surface) {
     glUseProgram(shader_program_blit_rgb_);
 
     int texture_unit = 0;
     glUniform1i(blit_rgb_sampler_location_, texture_unit);
     glActiveTexture(GL_TEXTURE0 + texture_unit);
     glBindTexture(GL_TEXTURE_RECTANGLE_ARB, texture_);
 
     DrawQuad(quad_);
 
     glBindTexture(GL_TEXTURE_RECTANGLE_ARB, 0); CHECK_GL_ERROR();
 
     // Fill the resize gutters with white.
-    if (window_size.width() > io_surface_size.width() ||
-        window_size.height() > io_surface_size.height()) {
+    if (window_size.width() > io_surface_size_.width() ||
+        window_size.height() > io_surface_size_.height()) {
       glUseProgram(shader_program_white_);
       SurfaceQuad filler_quad;
-      if (window_size.width() > io_surface_size.width()) {
+      if (window_size.width() > io_surface_size_.width()) {
         // Draw right-side gutter down to the bottom of the window.
-        filler_quad.set_rect(io_surface_size.width(), 0.0f,
+        filler_quad.set_rect(io_surface_size_.width(), 0.0f,
                              window_size.width(), window_size.height());
         DrawQuad(filler_quad);
       }
-      if (window_size.height() > io_surface_size.height()) {
+      if (window_size.height() > io_surface_size_.height()) {
         // Draw bottom gutter to the width of the IOSurface.
-        filler_quad.set_rect(0.0f, io_surface_size.height(),
-                             io_surface_size.width(), window_size.height());
+        filler_quad.set_rect(0.0f, io_surface_size_.height(),
+                             io_surface_size_.width(), window_size.height());
         DrawQuad(filler_quad);
       }
     }
 
     glUseProgram(0); CHECK_GL_ERROR();
   } else {
     // Should match the clear color of RenderWidgetHostViewMac.
     glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
     glClear(GL_COLOR_BUFFER_BIT);
   }
@@ skipping 111 matching lines @@
   if (!io_surface_.get()) {
     io_surface_handle_ = 0;
     return false;
   }
 
   io_surface_handle_ = io_surface_handle;
   pixel_io_surface_size_.SetSize(
       io_surface_support_->IOSurfaceGetWidth(io_surface_),
       io_surface_support_->IOSurfaceGetHeight(io_surface_));
 
+  // TODO(thakis): Keep track of the view size over IPC. At the moment,
+  // the correct view units are computed on first paint.
+  io_surface_size_ = pixel_io_surface_size_;
+
   quad_.set_size(pixel_io_surface_size_, pixel_io_surface_size_);
 
   GLenum target = GL_TEXTURE_RECTANGLE_ARB;
   glGenTextures(1, &texture_);
   glBindTexture(target, texture_);
   glTexParameterf(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   glTexParameterf(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST); CHECK_GL_ERROR();
   GLuint plane = 0;
   CGLError cglerror = io_surface_support_->CGLTexImageIOSurface2D(
       cglContext_,
@@ skipping 47 matching lines @@
 }
 
 void CompositingIOSurfaceMac::GlobalFrameDidChange() {
   [glContext_ update];
 }
 
 void CompositingIOSurfaceMac::ClearDrawable() {
   [glContext_ clearDrawable];
   UnrefIOSurface();
 }