DevTools: Add parent id to target descriptor in remote debugging.

chrome/browser/android/dev_tools_server.cc

Index: chrome/browser/android/dev_tools_server.cc
diff --git a/chrome/browser/android/dev_tools_server.cc b/chrome/browser/android/dev_tools_server.cc
index 246218eb9010dcf97f151ab89d953fec336042fd..091e9017852fbd6604c13cd09d018b4a81cd8d2b 100644
--- a/chrome/browser/android/dev_tools_server.cc
+++ b/chrome/browser/android/dev_tools_server.cc
@@ -79,6 +79,8 @@ static GURL GetFaviconURLForContents(WebContents* web_contents) {
 class TargetBase : public content::DevToolsTarget {
  public:
   // content::DevToolsTarget implementation:
+  virtual std::string GetParentId() const OVERRIDE { return std::string(); }
+
   virtual std::string GetTitle() const OVERRIDE { return title_; }
 
   virtual std::string GetDescription() const OVERRIDE { return std::string(); }