Blimp: create MessageDispatcher class.

blimp/common/compositor/blimp_layer_tree_settings.cc

Index: blimp/common/compositor/blimp_layer_tree_settings.cc
diff --git a/blimp/common/compositor/blimp_layer_tree_settings.cc b/blimp/common/compositor/blimp_layer_tree_settings.cc
index cef731791d865ad891c829562fbc4c927692e72f..007f563cd79ad41ddfd074d7ed15d6a3444a94fb 100644
--- a/blimp/common/compositor/blimp_layer_tree_settings.cc
+++ b/blimp/common/compositor/blimp_layer_tree_settings.cc
@@ -239,21 +239,30 @@ void PopulateCommonLayerTreeSettings(cc::LayerTreeSettings* settings) {
 // settings->use_external_begin_frame_source = true;
 
 #elif !defined(OS_MACOSX)
-  if (ui::IsOverlayScrollbarEnabled()) {
-    settings->scrollbar_animator = cc::LayerTreeSettings::THINNING;
-    settings->solid_color_scrollbar_color = SkColorSetARGB(128, 128, 128, 128);
-  } else {
-    settings->scrollbar_animator = cc::LayerTreeSettings::LINEAR_FADE;
-    settings->solid_color_scrollbar_color = SkColorSetARGB(128, 128, 128, 128);
-  }
-  settings->scrollbar_fade_delay_ms = 500;
-  settings->scrollbar_fade_resize_delay_ms = 500;
-  settings->scrollbar_fade_duration_ms = 300;
+  NOTIMPLEMENTED() << "Unresolved dependency TODO for native_theme.";

[nyquist, 2015/09/10 03:47:33]

This should be unnecessary now.

[Kevin M, 2015/09/10 18:11:17]

Done.

+  // TODO(dtrainor): Add blimp to ui/native_theme DEPS and re-enable
+  // this section.
+
+  // if (ui::IsOverlayScrollbarEnabled()) {
+  //   settings->scrollbar_animator = cc::LayerTreeSettings::THINNING;
+  //   settings->solid_color_scrollbar_color =
+  //       SkColorSetARGB(128, 128, 128, 128);
+  // } else {
+  //   settings->scrollbar_animator = cc::LayerTreeSettings::LINEAR_FADE;
+  //   settings->solid_color_scrollbar_color =
+  //       SkColorSetARGB(128, 128, 128, 128);
+  // }
+  // settings->scrollbar_fade_delay_ms = 500;
+  // settings->scrollbar_fade_resize_delay_ms = 500;
+  // settings->scrollbar_fade_duration_ms = 300;
 
   // When pinching in, only show the pinch-viewport overlay scrollbars if the
   // page scale is at least some threshold away from the minimum. i.e. don't
   // show the pinch scrollbars when at minimum scale.
-  settings->scrollbar_show_scale_threshold = 1.05f;
+  //
+  // TODO(dtrainor): Re-enable or delete this line entirely.
+  //     (LayerTreeSettings::scrollbar_show_scale_threshold does not exist.)
+  // settings->scrollbar_show_scale_threshold = 1.05f;
 #endif
 
   if (cmd.HasSwitch(switches::kEnableLowResTiling))