Reland of [WebRTC] A real ScreenCapturer test

webrtc/modules/desktop_capture/screen_drawer_unittest.cc

Index: webrtc/modules/desktop_capture/screen_drawer_unittest.cc
diff --git a/webrtc/modules/desktop_capture/screen_drawer_unittest.cc b/webrtc/modules/desktop_capture/screen_drawer_unittest.cc
index 345a962223ebdc4a670ca6f0c88b076d9bd2375b..b5f6ba5c1be2712ce2d734d7f941575c15aaca79 100644
--- a/webrtc/modules/desktop_capture/screen_drawer_unittest.cc
+++ b/webrtc/modules/desktop_capture/screen_drawer_unittest.cc
@@ -15,6 +15,7 @@
 #include "testing/gtest/include/gtest/gtest.h"
 #include "webrtc/base/random.h"
 #include "webrtc/base/timeutils.h"
+#include "webrtc/system_wrappers/include/logging.h"
 #include "webrtc/system_wrappers/include/sleep.h"
 
 namespace webrtc {
@@ -26,11 +27,16 @@ namespace webrtc {
 TEST(ScreenDrawerTest, DISABLED_DrawRectangles) {
   std::unique_ptr<ScreenDrawer> drawer = ScreenDrawer::Create();
   if (!drawer) {
-    // No ScreenDrawer implementation for current platform.
+    LOG(LS_WARNING) << "No ScreenDrawer implementation for current platform.";
+    return;
+  }
+
+  if (drawer->DrawableRegion().is_empty()) {
+    LOG(LS_WARNING) << "ScreenDrawer of current platform does not provide a "
+                       "non-empty DrawableRegion().";
     return;
   }
 
-  drawer->Clear();
   DesktopRect rect = drawer->DrawableRegion();
   Random random(rtc::TimeMicros());
   for (int i = 0; i < 100; i++) {
@@ -40,16 +46,15 @@ TEST(ScreenDrawerTest, DISABLED_DrawRectangles) {
     drawer->DrawRectangle(
         DesktopRect::MakeLTRB(left, top, random.Rand(left + 1, rect.right()),
                               random.Rand(top + 1, rect.bottom())),
-        random.Rand<uint32_t>());
+        RgbaColor(random.Rand<uint8_t>(), random.Rand<uint8_t>(),
+                  random.Rand<uint8_t>(), random.Rand<uint8_t>()));
 
     if (i == 50) {
       SleepMs(10000);
-      drawer->Clear();
     }
   }
 
   SleepMs(10000);
-  drawer->Clear();
 }
 
 }  // namespace webrtc