Decouple some graphics-related IsLowEndDevice() policies for 1GB devices.

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 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/renderer/gpu/render_widget_compositor.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 400 matching lines @@
   bool use_low_memory_policy =
       base::SysInfo::IsLowEndDevice() && !using_synchronous_compositor;
   if (use_low_memory_policy) {
     // 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;
 
     // RGBA_4444 textures are only enabled by default for low end devices
     // and are disabled for Android WebView as it doesn't support the format.
-    if (!cmd.HasSwitch(switches::kDisableRGBA4444Textures))
+    if (!cmd.HasSwitch(switches::kDisableRGBA4444Textures) &&
+        base::SysInfo::AmountOfPhysicalMemoryMB() <= 512)
       settings.renderer_settings.preferred_tile_format = cc::RGBA_4444;
   } 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;
   }
   // Webview does not own the surface so should not clear it.
   settings.renderer_settings.should_clear_root_render_pass =
       !using_synchronous_compositor;
@@ skipping 111 matching lines @@
   // Nexus 4/10(2GB)    256MB (normally 128MB)
   // Droid Razr M(1GB)  114MB (normally 57MB)
   // Galaxy Nexus(1GB)  100MB (normally 50MB)
   // Xoom(1GB)          100MB (normally 50MB)
   // Nexus S(low-end)   8MB (normally 8MB)
   // Note that the compositor now uses only some of this memory for
   // pre-painting and uses the rest only for 'emergencies'.
   if (actual.bytes_limit_when_visible == 0) {
     // NOTE: Non-low-end devices use only 50% of these limits,
     // except during 'emergencies' where 100% can be used.
-    if (!base::SysInfo::IsLowEndDevice()) {
-      if (physical_memory_mb >= 1536)
-        actual.bytes_limit_when_visible = physical_memory_mb / 8;  // >192MB
-      else if (physical_memory_mb >= 1152)
-        actual.bytes_limit_when_visible = physical_memory_mb / 8;  // >144MB
-      else if (physical_memory_mb >= 768)
-        actual.bytes_limit_when_visible = physical_memory_mb / 10;  // >76MB
-      else
-        actual.bytes_limit_when_visible = physical_memory_mb / 12;  // <64MB
-    } else {
-      // Low-end devices have 512MB or less memory by definition
-      // so we hard code the limit rather than relying on the heuristics
-      // above. Low-end devices use 4444 textures so we can use a lower limit.
+    if (physical_memory_mb >= 1536)
+      actual.bytes_limit_when_visible = physical_memory_mb / 8;  // >192MB
+    else if (physical_memory_mb >= 1152)
+      actual.bytes_limit_when_visible = physical_memory_mb / 8;  // >144MB
+    else if (physical_memory_mb >= 768)
+      actual.bytes_limit_when_visible = physical_memory_mb / 10;  // >76MB
+    else if (physical_memory_mb >= 513)
+      actual.bytes_limit_when_visible = physical_memory_mb / 12;  // <64MB
+    else
+      // Devices with this little RAM have very little headroom so we hardcode
+      // the limit rather than relying on the heuristics above.  (They also use
+      // 4444 textures so we can use a lower limit.)
       actual.bytes_limit_when_visible = 8;
-    }
+
     actual.bytes_limit_when_visible =
         actual.bytes_limit_when_visible * 1024 * 1024;
     // Clamp the observed value to a specific range on Android.
     actual.bytes_limit_when_visible = std::max(
         actual.bytes_limit_when_visible, static_cast<size_t>(8 * 1024 * 1024));
     actual.bytes_limit_when_visible =
         std::min(actual.bytes_limit_when_visible,
                  static_cast<size_t>(256 * 1024 * 1024));
   }
   actual.priority_cutoff_when_visible =
@@ skipping 569 matching lines @@
 void RenderWidgetCompositor::SetContentSourceId(uint32_t id) {
   layer_tree_host_->SetContentSourceId(id);
 }
 
 void RenderWidgetCompositor::SetLocalSurfaceId(
     const cc::LocalSurfaceId& local_surface_id) {
   layer_tree_host_->SetLocalSurfaceId(local_surface_id);
 }
 
 }  // namespace content