Restrict ETC1 power-of-two rounding to old IMG drivers.

chrome/browser/android/thumbnail/thumbnail_store.cc

Index: chrome/browser/android/thumbnail/thumbnail_store.cc
diff --git a/chrome/browser/android/thumbnail/thumbnail_store.cc b/chrome/browser/android/thumbnail/thumbnail_store.cc
index 52d92059275cf0530bf13f859855bb543ea756be..3f22a3e94a3abb31072889d644f36b0233450271 100644
--- a/chrome/browser/android/thumbnail/thumbnail_store.cc
+++ b/chrome/browser/android/thumbnail/thumbnail_store.cc
@@ -38,8 +38,6 @@ const int kCurrentExtraVersion = 1;
 // Indicates whether we prefer to have more free CPU memory over GPU memory.
 const bool kPreferCPUMemory = true;
 
-// TODO(): ETC1 texture sizes should be multiples of four, but some drivers only
-// allow power-of-two ETC1 textures.  Find better work around.
 size_t NextPowerOfTwo(size_t x) {
   --x;
   x |= x >> 1;
@@ -50,10 +48,18 @@ size_t NextPowerOfTwo(size_t x) {
   return x + 1;
 }
 
-gfx::Size GetEncodedSize(const gfx::Size& bitmap_size) {
+size_t RoundUpMod4(size_t x) {
+  return (x + 3) & ~3;
+}
+
+gfx::Size GetEncodedSize(const gfx::Size& bitmap_size, bool supports_npot) {
   DCHECK(!bitmap_size.IsEmpty());
-  return gfx::Size(NextPowerOfTwo(bitmap_size.width()),
-                   NextPowerOfTwo(bitmap_size.height()));
+  if (!supports_npot)
+    return gfx::Size(NextPowerOfTwo(bitmap_size.width()),
+                     NextPowerOfTwo(bitmap_size.height()));
+  else
+    return gfx::Size(RoundUpMod4(bitmap_size.width()),
+                     RoundUpMod4(bitmap_size.height()));
 }
 
 template<typename T>
@@ -365,11 +371,16 @@ void ThumbnailStore::CompressThumbnailIfNecessary(
                                          time_stamp,
                                          scale);
 
-  base::WorkerPool::PostTask(
-      FROM_HERE,
-      base::Bind(
-          &ThumbnailStore::CompressionTask, bitmap, post_compression_task),
-      true);
+  gfx::Size raw_data_size(bitmap.width(), bitmap.height());
+  gfx::Size encoded_size = GetEncodedSize(
+      raw_data_size, ui_resource_provider_->SupportsETC1NonPowerOfTwo());
+
+  base::WorkerPool::PostTask(FROM_HERE,
+                             base::Bind(&ThumbnailStore::CompressionTask,
+                                        bitmap,
+                                        encoded_size,
+                                        post_compression_task),
+                             true);
 }
 
 void ThumbnailStore::ReadNextThumbnail() {
@@ -539,6 +550,7 @@ void ThumbnailStore::PostWriteTask() {
 
 void ThumbnailStore::CompressionTask(
     SkBitmap raw_data,
+    gfx::Size encoded_size,
     const base::Callback<void(skia::RefPtr<SkPixelRef>, const gfx::Size&)>&
         post_compression_task) {
   skia::RefPtr<SkPixelRef> compressed_data;
@@ -550,7 +562,6 @@ void ThumbnailStore::CompressionTask(
     size_t pixel_size = 4;  // Pixel size is 4 bytes for kARGB_8888_Config.
     size_t stride = pixel_size * raw_data_size.width();
 
-    gfx::Size encoded_size = GetEncodedSize(raw_data_size);
     size_t encoded_bytes =
         etc1_get_encoded_data_size(encoded_size.width(), encoded_size.height());
     SkImageInfo info = {encoded_size.width(),