Implement all resolution change policies for desktop and tab capture.

media/base/video_util.h

Index: media/base/video_util.h
diff --git a/media/base/video_util.h b/media/base/video_util.h
index 7798ebe016e1a996bf1d0b022fe98ebbc702d53f..04013bc64778b54b65c52830ff3dace09efaa521 100644
--- a/media/base/video_util.h
+++ b/media/base/video_util.h
@@ -84,6 +84,26 @@ MEDIA_EXPORT void RotatePlaneByPixels(
 MEDIA_EXPORT gfx::Rect ComputeLetterboxRegion(const gfx::Rect& bounds,
                                               const gfx::Size& content);
 
+// Return a scaled |size| whose area is less than or equal to |target|, where
+// one of its dimensions is equal to |target|'s.  The aspect ratio of the result
+// is preserved as closely as possible.  If |size| is empty, its aspect ratio
+// would be undefined; and in this case an empty Size would be returned.
+MEDIA_EXPORT gfx::Size ScaleSizeToFitWithinTarget(const gfx::Size& size,
+                                                  const gfx::Size& target);
+
+// Return a scaled |size| whose area is greater than or equal to |target|, where
+// one of its dimensions is equal to |target|'s.  The aspect ratio of the result
+// is preserved as closely as possible.  If |size| is empty, its aspect ratio
+// would be undefined; and in this case an empty Size would be returned.
+MEDIA_EXPORT gfx::Size ScaleSizeToEncompassTarget(const gfx::Size& size,
+                                                  const gfx::Size& target);
+
+// Returns |size| with one of its dimensions increased such that the result
+// matches the aspect ratio of |target|.  If |target| is empty, its aspect ratio
+// would be undefined; and in this case an empty Size would be returned.
+MEDIA_EXPORT gfx::Size PadToMatchAspectRatio(const gfx::Size& size,
+                                             const gfx::Size& target);
+
 // Copy an RGB bitmap into the specified |region_in_frame| of a YUV video frame.
 // Fills the regions outside |region_in_frame| with black.
 MEDIA_EXPORT void CopyRGBToVideoFrame(const uint8* source,