Add a flag to disable partial raster in renderer

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 7f16e2831196d53b265b35f9a0912208d1b04bf2..493e390dac1378ab56a2625b5b1abd22c7094bd8 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -140,10 +140,10 @@ Compositor::Compositor(ui::ContextFactory* context_factory,
   settings.renderer_settings.use_rgba_4444_textures =
       command_line->HasSwitch(switches::kUIEnableRGBA4444Textures);
 
-  // Use PERSISTENT_MAP memory buffers to support partial tile raster for
-  // software raster into GpuMemoryBuffers.
+  // UI compositor always uses partial raster. Use PERSISTENT_MAP memory buffers

[danakj, 2015/10/08 15:18:43]

aside: i guess we shouldn't do this if use_zero_copy is true

[ericrk, 2015/10/13 23:03:45]

Added some more logic here to handle this case.

+  // to support partial tile raster for software raster into GpuMemoryBuffers.
+  settings.use_partial_raster = true;
   gfx::BufferUsage usage = gfx::BufferUsage::PERSISTENT_MAP;
-  settings.use_persistent_map_for_gpu_memory_buffers = true;
 
   for (size_t format = 0;
       format < static_cast<size_t>(gfx::BufferFormat::LAST) + 1; format++) {