SurfaceFlinger: Add sourceCrop to screenshot

Adds a sourceCrop Rect parameter to screenshot commands, which allows
clients to capture only a portion of the screen instead of the whole
screen.

Bug: 15137922
Change-Id: I629447573cd34ffb96334cde7ba02490b9ea06d8
diff --git a/cmds/screencap/screencap.cpp b/cmds/screencap/screencap.cpp
index 2efe4d3..6296dd1 100644
--- a/cmds/screencap/screencap.cpp
+++ b/cmds/screencap/screencap.cpp
@@ -141,7 +141,7 @@
 
     ScreenshotClient screenshot;
     sp<IBinder> display = SurfaceComposerClient::getBuiltInDisplay(displayId);
-    if (display != NULL && screenshot.update(display, false) == NO_ERROR) {
+    if (display != NULL && screenshot.update(display, Rect(), false) == NO_ERROR) {
         base = screenshot.getPixels();
         w = screenshot.getWidth();
         h = screenshot.getHeight();