Aggressively discard tiles on OS X to see if it improves

content/common/gpu/gpu_memory_manager.cc

Index: content/common/gpu/gpu_memory_manager.cc
diff --git a/content/common/gpu/gpu_memory_manager.cc b/content/common/gpu/gpu_memory_manager.cc
index 386ad90cf6ccee6a66fcaa9b1b60caf8029e7698..18b0264a81fa4c740b0015932432ae1b04943ac0 100644
--- a/content/common/gpu/gpu_memory_manager.cc
+++ b/content/common/gpu/gpu_memory_manager.cc
@@ -483,8 +483,15 @@ void GpuMemoryManager::Manage() {
       // Set the state when visible.
       allocation.renderer_allocation.bytes_limit_when_visible =
           bytes_limit_when_visible;
+      // Experiment to determine if aggressively discarding tiles on OS X
+      // results in greater stability.
+#if defined(OS_MACOSX)
+      allocation.renderer_allocation.priority_cutoff_when_visible =
+          GpuMemoryAllocationForRenderer::kPriorityCutoffAllowNiceToHave;
+#else
       allocation.renderer_allocation.priority_cutoff_when_visible =
           GpuMemoryAllocationForRenderer::kPriorityCutoffAllowEverything;
+#endif
 
       // Set the state when backgrounded.
       bool allow_allocation_when_backgrounded = false;