Implement device-ram client hints header

third_party/WebKit/public/platform/Platform.h

Index: third_party/WebKit/public/platform/Platform.h
diff --git a/third_party/WebKit/public/platform/Platform.h b/third_party/WebKit/public/platform/Platform.h
index f7360bf6cb93be8d78ffe7b66497474390e0ac11..ba065fafb74b3d35f0296c25f214c42b187dc00e 100644
--- a/third_party/WebKit/public/platform/Platform.h
+++ b/third_party/WebKit/public/platform/Platform.h
@@ -296,6 +296,13 @@ class BLINK_PLATFORM_EXPORT Platform {
   // Same as above, but always returns actual value, without any caches.
   virtual size_t ActualMemoryUsageMB() { return 0; }
 
+  // Returns the number of megabytes of physical memory on the current machine.
+  virtual size_t AmountOfPhysicalMemoryMB() { return 0; }
+
+  // Sets the physical memory size in megabytes for testing.
+  virtual void SetDevicePhysicalMemoryMBForTesting(int64_t physical_memory_mb) {
+  }
+
   // Return the number of of processors of the current machine.
   virtual size_t NumberOfProcessors() { return 0; }