[Paint Preview] Add test capture flag

Add a flag that

1. Adds a menu item to the main Android Menu
2. On press the menu item should trigger a paint preview capture
3. After completion the time taken and output size should be logged

Only compile in if the OS is Android and the Buildflag for
ENABLE_PAINT_PREVIEWS is set.

Bug: 1031612
Change-Id: Ib6cbf88838692d3d1dc77d448c805cd48e55ccbb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1954350
Commit-Queue: Calder Kitagawa <[email protected]>
Reviewed-by: David Trainor <[email protected]>
Reviewed-by: Mehran Mahmoudi <[email protected]>
Reviewed-by: Ian Vollick <[email protected]>
Cr-Commit-Position: refs/heads/master@{#728937}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 416c70c..164fa82b 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -11,6 +11,7 @@
 #include "build/buildflag.h"
 #include "chrome/common/buildflags.h"
 #include "components/nacl/common/buildflags.h"
+#include "components/paint_preview/buildflags/buildflags.h"
 #include "components/spellcheck/spellcheck_buildflags.h"
 #include "device/vr/buildflags/buildflags.h"
 #include "media/media_buildflags.h"
@@ -2415,6 +2416,11 @@
 extern const char kNaclDescription[];
 #endif  // ENABLE_NACL
 
+#if BUILDFLAG(ENABLE_PAINT_PREVIEW) && defined(OS_ANDROID)
+extern const char kPaintPreviewTestName[];
+extern const char kPaintPreviewTestDescription[];
+#endif  // ENABLE_PAINT_PREVIEW && defined(OS_ANDROID)
+
 #if BUILDFLAG(ENABLE_PLUGINS)
 
 #if defined(OS_CHROMEOS)