Add ctrl+mousewheel plumbing to MimeHandlerView.

This will zoom in/out the view properly.

This CL is dependant on http://crrev.com/597653002

BUG=416332
Test=Load chrome with --enable-mime-handler-view and --out-of-process-pdf
Navigate to a pdf file, Ctrl + wheel up and down should zoom in/out the pdf
properly.

Review URL: https://codereview.chromium.org/591243003

Cr-Commit-Position: refs/heads/master@{#296455}

chrome/browser/guest_view/mime_handler_view/chrome_mime_handler_view_guest_delegate.cc

@@ -4,6 +4,7 @@
 
 #include "chrome/browser/guest_view/mime_handler_view/chrome_mime_handler_view_guest_delegate.h"
 
+#include "chrome/browser/chrome_page_zoom.h"
 #include "chrome/browser/ui/pdf/chrome_pdf_web_contents_helper_client.h"
 #include "components/pdf/browser/pdf_web_contents_helper.h"
 #include "extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h"
@@ -41,3 +42,11 @@ void ChromeMimeHandlerViewGuestDelegate::AttachHelpers() {
       scoped_ptr<pdf::PDFWebContentsHelperClient>(
           new ChromePDFWebContentsHelperClient()));
 }
+
+void ChromeMimeHandlerViewGuestDelegate::ChangeZoom(bool zoom_in) {
+  // TODO(lazyboy): Move this to //extensions once ZoomController and friends
+  // move to //extensions.
+  chrome_page_zoom::Zoom(
+      guest_->embedder_web_contents(),
+      zoom_in ? content::PAGE_ZOOM_IN : content::PAGE_ZOOM_OUT);
+}

chrome/browser/guest_view/mime_handler_view/chrome_mime_handler_view_guest_delegate.h

@@ -18,7 +18,9 @@ class ChromeMimeHandlerViewGuestDelegate
       extensions::MimeHandlerViewGuest* guest);
   virtual ~ChromeMimeHandlerViewGuestDelegate();
 
+  // MimeHandlerViewGuestDelegate.
   virtual void AttachHelpers() OVERRIDE;
+  virtual void ChangeZoom(bool zoom_in) OVERRIDE;
 
  private:
   extensions::MimeHandlerViewGuest* guest_;  // Owns us.

extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc

@@ -131,6 +131,11 @@ void MimeHandlerViewGuest::DidInitialize() {
     delegate_->AttachHelpers();
 }
 
+void MimeHandlerViewGuest::ContentsZoomChange(bool zoom_in) {
+  if (delegate_)
+    delegate_->ChangeZoom(zoom_in);
+}
+
 void MimeHandlerViewGuest::HandleKeyboardEvent(
     WebContents* source,
     const content::NativeWebKeyboardEvent& event) {

extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.h

@@ -37,6 +37,7 @@ class MimeHandlerViewGuest : public GuestView<MimeHandlerViewGuest>,
   virtual void DidInitialize() OVERRIDE;
 
   // WebContentsDelegate implementation.
+  virtual void ContentsZoomChange(bool zoom_in) OVERRIDE;
   virtual void HandleKeyboardEvent(
       content::WebContents* source,
       const content::NativeWebKeyboardEvent& event) OVERRIDE;

extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest_delegate.h

@@ -24,6 +24,10 @@ class MimeHandlerViewGuestDelegate {
   // Attaches helpers upon initializing the WebContents.
   virtual void AttachHelpers() {}
 
+  // Request to change the zoom level of the top level page containing
+  // this view.
+  virtual void ChangeZoom(bool zoom_in) {}
+
  private:
   DISALLOW_COPY_AND_ASSIGN(MimeHandlerViewGuestDelegate);
 };