Test runner: make inspector tests reuse a single inspector process.

content/shell/browser/shell_devtools_frontend.h

Index: content/shell/browser/shell_devtools_frontend.h
diff --git a/content/shell/browser/shell_devtools_frontend.h b/content/shell/browser/shell_devtools_frontend.h
index 038b88bff932bea231ce395f9771a53943364c05..c86afb6266e75cd33d0630f453033443a40f6633 100644
--- a/content/shell/browser/shell_devtools_frontend.h
+++ b/content/shell/browser/shell_devtools_frontend.h
@@ -30,12 +30,20 @@ class ShellDevToolsFrontend : public WebContentsObserver,
   void InspectElementAt(int x, int y);
   void Close();
 
+  void SwitchToTarget(WebContents* inspected_contents);
+  void DisconnectFromTarget();
+
   Shell* frontend_shell() const { return frontend_shell_; }
 
  protected:
   ShellDevToolsFrontend(Shell* frontend_shell, DevToolsAgentHost* agent_host);
   ~ShellDevToolsFrontend() override;
 
+  // content::DevToolsAgentHostClient implementation.
+  void AgentHostClosed(DevToolsAgentHost* agent_host, bool replaced) override;
+  void DispatchProtocolMessage(DevToolsAgentHost* agent_host,
+                               const std::string& message) override;
+
  private:
   // WebContentsObserver overrides
   void RenderViewCreated(RenderViewHost* render_view_host) override;
@@ -46,11 +54,6 @@ class ShellDevToolsFrontend : public WebContentsObserver,
   void HandleMessageFromDevToolsFrontendToBackend(
       const std::string& message) override;
 
-  // content::DevToolsAgentHostClient implementation.
-  void DispatchProtocolMessage(DevToolsAgentHost* agent_host,
-                               const std::string& message) override;
-  void AgentHostClosed(DevToolsAgentHost* agent_host, bool replaced) override;
-
   Shell* frontend_shell_;
   scoped_refptr<DevToolsAgentHost> agent_host_;
   scoped_ptr<DevToolsFrontendHost> frontend_host_;