Remove unnecessary decoded frame size overflow check

third_party/WebKit/Source/platform/image-decoders/ImageDecoder.cpp

Index: third_party/WebKit/Source/platform/image-decoders/ImageDecoder.cpp
diff --git a/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.cpp b/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.cpp
index e7eac4b4a3f696ab1f6871dafc99fab7d4d1b4e3..a42a39a3749ac7e710e8eafbb71472899a394c3f 100644
--- a/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.cpp
+++ b/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.cpp
@@ -407,13 +407,8 @@ void ImageDecoder::UpdateAggressivePurging(size_t index) {
   // As we decode we will learn the total number of frames, and thus total
   // possible image memory used.
 
-  const uint64_t frame_area = DecodedSize().Area();
-  const uint64_t frame_memory_usage = frame_area * 4;  // 4 bytes per pixel
-  if (frame_memory_usage / 4 != frame_area) {          // overflow occurred

[Srirama, 2017/05/30 07:07:39]

though it looks like it is doing nothing, this would have been added to detect
overflow. Please check the history of the CL why it was added to get a better
understanding. If it needs to be removed probably we need to remove the below
part of the code as well.
Anyway i will leave it to scroggo@ and noel@ to comment on this.

-    purge_aggressively_ = true;
-    return;
-  }
-
+  const uint64_t frame_memory_usage =
+      DecodedSize().Area() * 4;  // 4 bytes per pixel
   const uint64_t total_memory_usage = frame_memory_usage * index;
   if (total_memory_usage / frame_memory_usage != index) {  // overflow occurred
     purge_aggressively_ = true;