chrome/blink: Add functionality for in-product help for media elements.

third_party/WebKit/Source/core/page/ChromeClient.h

Index: third_party/WebKit/Source/core/page/ChromeClient.h
diff --git a/third_party/WebKit/Source/core/page/ChromeClient.h b/third_party/WebKit/Source/core/page/ChromeClient.h
index 1b1ecbd0f6faf853dbc65a88b6495946e7ccd634..c95fa82aeea5dcb500647b509d9bd17245cb57e1 100644
--- a/third_party/WebKit/Source/core/page/ChromeClient.h
+++ b/third_party/WebKit/Source/core/page/ChromeClient.h
@@ -45,6 +45,7 @@
 #include "public/platform/WebDragOperation.h"
 #include "public/platform/WebEventListenerProperties.h"
 #include "public/platform/WebFocusType.h"
+#include "public/web/WebMediaIPH.h"
 
 // To avoid conflicts with the CreateWindow macro from the Windows SDK...
 #undef CreateWindow
@@ -363,6 +364,10 @@ class CORE_EXPORT ChromeClient : public PlatformChromeClient {
     return nullptr;
   }
 
+  virtual std::unique_ptr<WebMediaIPH> CreateWebMediaIPH(LocalFrame*) {
+    return nullptr;
+  }
+
   virtual void RequestDecode(
       LocalFrame*,
       const PaintImage& image,