Deal with alpha values when building PNG in chrome.tabs.captureVisibleTab().

chrome/browser/extensions/extension_tabs_module.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/extension_tabs_module.h"
 
 #include "base/base64.h"
 #include "base/string_util.h"
 #include "chrome/browser/browser.h"
 #include "chrome/browser/browser_list.h"
@@ skipping 871 matching lines @@
 // For example, some uncommon X11 visual modes are not supported by
 // CopyFromBackingStore().
 bool CaptureVisibleTabFunction::CaptureSnapshotFromBackingStore(
     BackingStore* backing_store) {
 
   skia::PlatformCanvas temp_canvas;
   if (!backing_store->CopyFromBackingStore(gfx::Rect(backing_store->size()),
                                            &temp_canvas)) {
     return false;
   }
+  LOG(INFO) << "captureVisibleTab() Got image from backing store.";
+
   SendResultFromBitmap(
       temp_canvas.getTopPlatformDevice().accessBitmap(false));
   return true;
 }
 
 // If a backing store was not available in CaptureVisibleTabFunction::RunImpl,
 // than the renderer was asked for a snapshot.  Listen for a notification
 // that the snapshot is available.
 void CaptureVisibleTabFunction::Observe(NotificationType type,
                                         const NotificationSource& source,
                                         const NotificationDetails& details) {
   DCHECK(type == NotificationType::TAB_SNAPSHOT_TAKEN);
 
   const SkBitmap *screen_capture = Details<const SkBitmap>(details).ptr();
   const bool error = screen_capture->empty();
 
   if (error) {
     error_ = keys::kInternalVisibleTabCaptureError;
     SendResponse(false);
   } else {
+    LOG(INFO) << "captureVisibleTab() Got image from renderer.";
     SendResultFromBitmap(*screen_capture);
   }
 
   Release();  // Balanced in CaptureVisibleTabFunction::RunImpl().
 }
 
 // Turn a bitmap of the screen into an image, set that image as the result,
 // and call SendResponse().
 void CaptureVisibleTabFunction::SendResultFromBitmap(
     const SkBitmap& screen_capture) {
   scoped_refptr<RefCountedBytes> image_data(new RefCountedBytes);
   SkAutoLockPixels screen_capture_lock(screen_capture);
   bool encoded = false;
   std::string mime_type;
   switch (image_format_) {
     case FORMAT_JPEG:
       encoded = gfx::JPEGCodec::Encode(
           reinterpret_cast<unsigned char*>(screen_capture.getAddr32(0, 0)),
           gfx::JPEGCodec::FORMAT_BGRA,
           screen_capture.width(),
           screen_capture.height(),
-          static_cast<int>(screen_capture.rowBytes()), image_quality_,
+          static_cast<int>(screen_capture.rowBytes()),
+          image_quality_,
           &image_data->data);
       mime_type = keys::kMimeTypeJpeg;
       break;
     case FORMAT_PNG:
-      encoded = gfx::PNGCodec::Encode(
-          reinterpret_cast<unsigned char*>(screen_capture.getAddr32(0, 0)),
-          gfx::PNGCodec::FORMAT_BGRA,
-          screen_capture.width(),
-          screen_capture.height(),
-          static_cast<int>(screen_capture.rowBytes()), false,
+      encoded = gfx::PNGCodec::EncodeBGRASkBitmap(
+          screen_capture,
+          true,  // Discard transparency.
           &image_data->data);
       mime_type = keys::kMimeTypePng;
       break;
     default:
       NOTREACHED() << "Invalid image format.";
   }
 
   if (!encoded) {
     error_ = ExtensionErrorUtils::FormatErrorMessage(
         keys::kInternalVisibleTabCaptureError, "");
@@ skipping 140 matching lines @@
 }
 
 static GURL ResolvePossiblyRelativeURL(std::string url_string,
                                        Extension* extension) {
   GURL url = GURL(url_string);
   if (!url.is_valid())
     url = extension->GetResourceURL(url_string);
 
   return url;
 }