Limit image decoded size on low end Android devices

webkit/child/webkitplatformsupport_impl.cc

Index: webkit/child/webkitplatformsupport_impl.cc
diff --git a/webkit/child/webkitplatformsupport_impl.cc b/webkit/child/webkitplatformsupport_impl.cc
index 50c9a787d4ac800dbb2a7ae1b38e2326ddac6e9b..d1c5960b3315397566764244443880627a11bb92 100644
--- a/webkit/child/webkitplatformsupport_impl.cc
+++ b/webkit/child/webkitplatformsupport_impl.cc
@@ -51,6 +51,10 @@
 #include "webkit/common/user_agent/user_agent.h"
 #include "webkit/glue/webkit_glue.h"
 
+#if defined(OS_ANDROID)
+#include "base/android/sys_utils.h"
+#endif
+
 using WebKit::WebAudioBus;
 using WebKit::WebCookie;
 using WebKit::WebData;
@@ -879,6 +883,15 @@ bool WebKitPlatformSupportImpl::memoryAllocatorWasteInBytes(size_t* size) {
   return base::allocator::GetAllocatorWasteSize(size);
 }
 
+size_t WebKitPlatformSupportImpl::maxImageDecodedBytes() {
+#if defined(OS_ANDROID)
+  // Limit image decoded size to 3M pixels on low end devices.
+  if (base::android::SysUtils::IsLowEndDevice())
+    return 3 * 1000 * 1000 * 4;  // 4 is maximum number of bytes per pixel.
+#endif
+  return 0;  // Unlimited.

[tony, 2013/09/20 22:27:04]

Having 0 mean unlimited is a bit weird.  Why not return
numeric_limits<size_t>::max()?

It seems inconsistent that a phone with <= 512mb has a limit, but if a laptop or
desktop has <= 512mb, we continue to decode the image.  Is it worth trying to
scale the image decode size based on memory and/or swap space?

Out of curiosity, are there many phones that can run Chrome (i.e., have Android
OS 4.x) and have <= 512mb of memory?

[Xianzhu, 2013/09/20 23:13:47]

Done.
For now we want to focus on the bug (which is Android-only) and limit this CL to
Android only which will ease the merge process.

+}
+
 void WebKitPlatformSupportImpl::SuspendSharedTimer() {
   ++shared_timer_suspended_;
 }