<webview>: Fix missing transparency in captureVisibleRegion().

extensions/browser/api/web_contents_capture_client.cc

Index: extensions/browser/api/web_contents_capture_client.cc
diff --git a/extensions/browser/api/web_contents_capture_client.cc b/extensions/browser/api/web_contents_capture_client.cc
index 78c3760667ec99357e349436c3d47990c00f47dd..53ba3051ba8206ef73d82b7b6ca49e806addad98 100644
--- a/extensions/browser/api/web_contents_capture_client.cc
+++ b/extensions/browser/api/web_contents_capture_client.cc
@@ -120,8 +120,8 @@ bool WebContentsCaptureClient::EncodeBitmap(const SkBitmap& bitmap,
     case api::extension_types::IMAGE_FORMAT_PNG:
       encoded =
           gfx::PNGCodec::EncodeBGRASkBitmap(bitmap,
-                                            true,  // Discard transparency.
-                                            &data);
+                                            /* Don't discard transparency */

[wjmaclean, 2016/04/06 12:39:20]

This comment could be re-worded, something like "Don't discard transparency if
client allows transparency."

[avallee, 2016/04/06 14:12:27]

Done.

+                                            !ContentsHasTransparency(), &data);
       mime_type = kMimeTypePng;
       break;
     default: