Expose a low-end device mode override flags for non-android OSs as well

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 7d8700f3dd79e9694600ecfbbf7af48cb7e8506e..7225f7ea33b1219f7d3acbb3fc0606543b3aefb7 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -15,6 +15,7 @@
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/sys_utils.h"
 #include "build/build_config.h"
 #include "cc/base/switches.h"
 #include "cc/debug/benchmark_instrumentation.h"
@@ -68,7 +69,6 @@
 #include "webkit/renderer/compositor_bindings/web_rendering_stats_impl.h"
 
 #if defined(OS_ANDROID)
-#include "base/android/sys_utils.h"
 #include "content/renderer/android/synchronous_compositor_factory.h"
 #endif
 
@@ -938,10 +938,8 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
   if (command_line.HasSwitch(cc::switches::kCompositeToMailbox)) {
     DCHECK(is_threaded_compositing_enabled_);
     cc::ResourceFormat format = cc::RGBA_8888;
-#if defined(OS_ANDROID)
-    if (base::android::SysUtils::IsLowEndDevice())
+    if (base::SysUtils::IsLowEndDevice())
       format = cc::RGB_565;
-#endif
     return scoped_ptr<cc::OutputSurface>(
         new MailboxOutputSurface(
             routing_id(),
@@ -2845,27 +2843,29 @@ RenderWidget::CreateGraphicsContext3D(
     return scoped_ptr<WebGraphicsContext3DCommandBufferImpl>();
 
   WebGraphicsContext3DCommandBufferImpl::SharedMemoryLimits limits;
-#if defined(OS_ANDROID)
   // If we raster too fast we become upload bound, and pending
   // uploads consume memory. For maximum upload throughput, we would
   // want to allow for upload_throughput * pipeline_time of pending
   // uploads, after which we are just wasting memory. Since we don't
   // know our upload throughput yet, this just caps our memory usage.
-  size_t divider = 1;
-  if (base::android::SysUtils::IsLowEndDevice())
-    divider = 6;
+
   // For reference Nexus10 can upload 1MB in about 2.5ms.
-  const double max_mb_uploaded_per_ms = 2.0 / (5 * divider);
+  const double max_mb_uploaded_per_ms = 2.0 / 5;
   // Deadline to draw a frame to achieve 60 frames per second.
   const size_t kMillisecondsPerFrame = 16;
   // Assuming a two frame deep pipeline between the CPU and the GPU.
-  size_t max_transfer_buffer_usage_mb =
+  const size_t max_transfer_buffer_usage_mb =
       static_cast<size_t>(2 * kMillisecondsPerFrame * max_mb_uploaded_per_ms);
   static const size_t kBytesPerMegabyte = 1024 * 1024;
   // We keep the MappedMemoryReclaimLimit the same as the upload limit
   // to avoid unnecessarily stalling the compositor thread.
-  limits.mapped_memory_reclaim_limit =
-      max_transfer_buffer_usage_mb * kBytesPerMegabyte;
+  if (base::SysUtils::IsLowEndDevice())

[piman, 2014/01/21 21:23:49]

needs braces

+    limits.mapped_memory_reclaim_limit =
+        max_transfer_buffer_usage_mb / 6 * kBytesPerMegabyte;
+#if defined(OS_ANDROID)
+  else
+    limits.mapped_memory_reclaim_limit =
+        max_transfer_buffer_usage_mb * kBytesPerMegabyte;
 #endif
 
   scoped_ptr<WebGraphicsContext3DCommandBufferImpl> context(