Use webrtc::DesktopCapturer for screen capturer implementation.

media/video/capture/screen/differ.cc

Index: media/video/capture/screen/differ.cc
diff --git a/media/video/capture/screen/differ.cc b/media/video/capture/screen/differ.cc
index 3296903824015b4d45275282e1a9f30385f0450f..20e78c161811dcf3bc5e30e242c312ec77d4c487 100644
--- a/media/video/capture/screen/differ.cc
+++ b/media/video/capture/screen/differ.cc
@@ -27,11 +27,10 @@ Differ::Differ(int width, int height, int bpp, int stride) {
 Differ::~Differ() {}
 
 void Differ::CalcDirtyRegion(const void* prev_buffer, const void* curr_buffer,
-                             SkRegion* region) {
+                             webrtc::DesktopRegion* region) {
   if (!region) {

[alexeypa (please no reviews), 2013/05/08 22:24:59]

The whole purpose of this method is to return |region|. The caller should not be
able to pass NULL. Remove this check.

[Sergey Ulanov, 2013/05/09 18:49:02]

Done

     return;
   }
-  region->setEmpty();
 
   if (!prev_buffer || !curr_buffer) {

[alexeypa (please no reviews), 2013/05/08 22:24:59]

It looks like the callers make sure that |prev_buffer| and |curr_buffer| are not
NULL. Remove this check.

[Sergey Ulanov, 2013/05/09 18:49:02]

Done.

     return;
@@ -131,9 +130,9 @@ DiffInfo Differ::DiffPartialBlock(const uint8* prev_buffer,
   return 0;
 }
 
-void Differ::MergeBlocks(SkRegion* region) {
+void Differ::MergeBlocks(webrtc::DesktopRegion* region) {
   DCHECK(region);

[alexeypa (please no reviews), 2013/05/08 22:24:59]

nit: remove DCHECK. |region->Clear()| will crash if |region| is NULL just fine.

[Sergey Ulanov, 2013/05/09 18:49:02]

Done.

-  region->setEmpty();
+  region->Clear();
 
   uint8* diff_info_row_start = static_cast<uint8*>(diff_info_.get());
   int diff_info_stride = diff_info_width_ * sizeof(DiffInfo);
@@ -195,8 +194,8 @@ void Differ::MergeBlocks(SkRegion* region) {
         if (top + height > height_) {
           height = height_ - top;
         }
-        region->op(SkIRect::MakeXYWH(left, top, width, height),
-                   SkRegion::kUnion_Op);
+        region->AddRect(
+            webrtc::DesktopRect::MakeXYWH(left, top, width, height));
       }
 
       // Increment to next block in this row.