Use webrtc::DesktopCapturer for screen capturer implementation.

remoting/host/daemon_process.cc

Index: remoting/host/daemon_process.cc
diff --git a/remoting/host/daemon_process.cc b/remoting/host/daemon_process.cc
index 50c1b454e39d5f6f9490f97f6e5f685aaf72cacf..4d0e9cb0db77b2bd22a27fa5548a62f003ae5c51 100644
--- a/remoting/host/daemon_process.cc
+++ b/remoting/host/daemon_process.cc
@@ -29,9 +29,9 @@ namespace {
 const char kApplicationName[] = "chromoting";
 
 std::ostream& operator<<(std::ostream& os, const ScreenResolution& resolution) {
-  return os << resolution.dimensions_.width() << "x"
-            << resolution.dimensions_.height() << " at "
-            << resolution.dpi_.x() << "x" << resolution.dpi_.y() << " DPI";
+  return os << resolution.dimensions().width() << "x"
+            << resolution.dimensions().height() << " at "
+            << resolution.dpi().x() << "x" << resolution.dpi().y() << " DPI";
 }
 
 }  // namespace
@@ -188,13 +188,6 @@ void DaemonProcess::CreateDesktopSession(int terminal_id,
   // Terminal IDs cannot be reused. Update the expected next terminal ID.
   next_terminal_id_ = std::max(next_terminal_id_, terminal_id + 1);
 
-  // Validate |resolution| and restart the sender if it is not valid.
-  if (!resolution.IsValid()) {

[alexeypa (please no reviews), 2013/04/26 21:33:58]

|resolution| is received from less privileged process. We have to validate it
and crash the sender if it is bogus. I.e. don't delete this code.

Also this method (unlike DaemonProcess::SetScreenResolution) should allow screen
size 0x0. IsEmpty() from this CL will not allow this.

[Sergey Ulanov, 2013/05/07 22:25:50]

There is a check in chromoting_param_traits.cc where incoming messages are
parsed.

-    LOG(ERROR) << "Invalid resolution specified: " << resolution;
-    CrashNetworkProcess(FROM_HERE);
-    return;
-  }
-
   // Create the desktop session.
   scoped_ptr<DesktopSession> session = DoCreateDesktopSession(
       terminal_id, resolution, virtual_terminal);
@@ -223,7 +216,7 @@ void DaemonProcess::SetScreenResolution(int terminal_id,
   }
 
   // Validate |resolution| and restart the sender if it is not valid.
-  if (!resolution.IsValid()) {
+  if (resolution.IsEmpty()) {

[alexeypa (please no reviews), 2013/04/26 21:33:58]

nit: IsEmpty() seems to be OK in this case since you changed it to check for
negative screen size. But 0x0 was legally allowed in some cases before. Be
careful when changing IsValid to IsEmpty.

[Sergey Ulanov, 2013/05/07 22:25:50]

Yes, I understand that there is a difference. Intention is that ScreenResolution
should never be initialized with invalid values - it DCHECKS for this in
constructor.

     LOG(ERROR) << "Invalid resolution specified: " << resolution;
     CrashNetworkProcess(FROM_HERE);
     return;