GPU: Adjust memory and use the soft-limit.

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index 24519d8376957ec8f5804e516e8f11c7af59ef0a..da770954da5f57656a1b3dfd5bcc5e1312ec530d 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -262,6 +262,20 @@ scoped_ptr<RenderWidgetCompositor> RenderWidgetCompositor::Create(
       base::android::SysUtils::IsLowEndDevice() &&
       !widget->UsingSynchronousRendererCompositor() &&
       !cmd->HasSwitch(cc::switches::kDisable4444Textures);
+  if (widget->UsingSynchronousRendererCompositor()) {
+    // TODO(boliu): Set this ratio for Webview.

[aelias_OOO_until_Jul13, 2014/02/15 00:55:17]

How about just using the same policy for WebView until we see evidence an
adjustment is needed?

[epenner, 2014/02/15 01:02:27]

I think their limits are not as excessive as ours. Possibly already on the low
side. I asked Bo and he said to just leave it for him to manually test and
fiddle with.

+  } else if (base::android::SysUtils::IsLowEndDevice()) {
+    // On low-end we want to be very carefull about killing other
+    // apps. So initially we use 50% more memory to avoid flickering
+    // or raster-on-demand.
+    settings.max_memory_for_prepaint_percentage = 67;
+  } else {
+    // On other devices we have increased memory excessively to avoid
+    // raster-on-demand already, so now we reserve 50% _only_ to avoid
+    // raster-on-demand, and use 50% of the memory otherwise.
+    settings.max_memory_for_prepaint_percentage = 50;
+  }
+
 #elif !defined(OS_MACOSX)
   if (IsOverlayScrollbarEnabled()) {
     settings.scrollbar_animator = cc::LayerTreeSettings::Thinning;