cc: Make 1/4th default low res scale.

This patch makes the default low res scale factor be 0.25 * high res
scale factor. The reasoning is that 0.125 looks too blurry. With low
quality low res tiles in play, 0.25 should still incur a performance
penalty, but it shouldn't be too bad, and look a bit better.

BUG=268203

Review URL: https://codereview.chromium.org/22144008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226371 0039d316-1c4b-4281-b951-d872f2087c98

cc/layers/picture_layer_impl_unittest.cc

@@ -742,21 +742,21 @@ TEST_F(PictureLayerImplTest, DontAddLowResDuringAnimation) {
   EXPECT_BOTH_EQ(num_tilings(), 2u);
 
   // Page scale animation, new high res, but not new low res because animating.
-  contents_scale = 4.f;
-  page_scale = 4.f;
+  contents_scale = 2.f;
+  page_scale = 2.f;
   animating_transform = true;
   SetContentsScaleOnBothLayers(
       contents_scale, device_scale, page_scale, animating_transform);
-  EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), 4.f);
+  EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), 2.f);
   EXPECT_BOTH_EQ(LowResTiling()->contents_scale(), low_res_factor);
   EXPECT_BOTH_EQ(num_tilings(), 3u);
 
   // Stop animating, new low res gets created for final page scale.
   animating_transform = false;
   SetContentsScaleOnBothLayers(
       contents_scale, device_scale, page_scale, animating_transform);
-  EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), 4.f);
-  EXPECT_BOTH_EQ(LowResTiling()->contents_scale(), 4.f * low_res_factor);
+  EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), 2.f);
+  EXPECT_BOTH_EQ(LowResTiling()->contents_scale(), 2.f * low_res_factor);
   EXPECT_BOTH_EQ(num_tilings(), 4u);
 }
 

cc/trees/layer_tree_settings.cc

@@ -37,7 +37,7 @@ LayerTreeSettings::LayerTreeSettings()
       maximum_number_of_failed_draws_before_draw_is_forced_(3),
       layer_transforms_should_scale_layer_contents(false),
       minimum_contents_scale(0.0625f),
-      low_res_contents_scale_factor(0.125f),
+      low_res_contents_scale_factor(0.25f),
       top_controls_height(0.f),
       top_controls_show_threshold(0.5f),
       top_controls_hide_threshold(0.5f),

content/browser/gpu/gpu_data_manager_impl_private.cc

@@ -258,10 +258,6 @@ void ApplyAndroidWorkarounds(const gpu::GPUInfo& gpu_info,
   std::string renderer(StringToLowerASCII(gpu_info.gl_renderer));
   bool is_img =
       gpu_info.gl_vendor.find("Imagination") != std::string::npos;
-  bool is_nexus7 =
-      gpu_info.machine_model.find("Nexus 7") != std::string::npos;
-  bool is_nexus10 =
-      gpu_info.machine_model.find("Nexus 10") != std::string::npos;
 
   gfx::DeviceDisplayInfo info;
   int default_tile_size = 256;
@@ -300,14 +296,6 @@ void ApplyAndroidWorkarounds(const gpu::GPUInfo& gpu_info,
     command_line->AppendSwitchASCII(
         switches::kDefaultTileHeight, size.str());
   }
-
-  // Increase the resolution of low resolution tiles for Nexus tablets.
-  if ((is_nexus7 || is_nexus10) &&
-      !command_line->HasSwitch(
-          cc::switches::kLowResolutionContentsScaleFactor)) {
-    command_line->AppendSwitchASCII(
-        cc::switches::kLowResolutionContentsScaleFactor, "0.25");
-  }
 }
 #endif  // OS_ANDROID