Implement Platform::getUniqueIdForProcess.

components/html_viewer/blink_platform_impl.cc

Index: components/html_viewer/blink_platform_impl.cc
diff --git a/components/html_viewer/blink_platform_impl.cc b/components/html_viewer/blink_platform_impl.cc
index 6a8032b3d2bf60a475eb84a552061814f3de5bbc..04b5ef48ac567347c6916efc267d96e1c0ba8395 100644
--- a/components/html_viewer/blink_platform_impl.cc
+++ b/components/html_viewer/blink_platform_impl.cc
@@ -13,6 +13,7 @@
 #include "base/thread_task_runner_handle.h"
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
 #include "components/html_viewer/blink_resource_constants.h"
 #include "components/html_viewer/web_clipboard_impl.h"
 #include "components/html_viewer/web_cookie_jar_impl.h"
@@ -133,6 +134,12 @@ blink::WebCompositorSupport* BlinkPlatformImpl::compositorSupport() {
   return &compositor_support_;
 }
 
+uint32_t BlinkPlatformImpl::getUniqueIdForProcess() {
+  // TODO(rickyz): Replace this with base::GetUniqueIdForProcess when that's
+  // ready.
+  return base::trace_event::TraceLog::GetInstance()->process_id();
+}
+
 void BlinkPlatformImpl::createMessageChannel(
     blink::WebMessagePortChannel** channel1,
     blink::WebMessagePortChannel** channel2) {