Implement a shell of FindRequestManager, and hook it up to WebContentsImpl.

content/public/browser/web_contents.h

Index: content/public/browser/web_contents.h
diff --git a/content/public/browser/web_contents.h b/content/public/browser/web_contents.h
index 96a3feb63b6dbe947fb39dcc272eeb372bdedfe7..800d24ac2706249a19cf87fd4904663f9be417b9 100644
--- a/content/public/browser/web_contents.h
+++ b/content/public/browser/web_contents.h
@@ -707,6 +707,13 @@ class WebContents : public PageNavigator,
   CONTENT_EXPORT static WebContents* FromJavaWebContents(
       jobject jweb_contents_android);
   virtual base::android::ScopedJavaLocalRef<jobject> GetJavaWebContents() = 0;
+
+  // Selects and zooms to the find result nearest to the point (x,y) defined in
+  // find-in-page coordinates.

[ncarter (slow), 2016/04/06 19:08:03]

Could you document what find-in-page coordinates are?

[paulmeyer, 2016/04/07 17:36:15]

Find-in-page coordinates are explained in FindInPageCoordinates.h
(https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...).

I just copied this comment from the existing
FindTabHelper::ActivateNearestFindResult() method. You will notice if you search
for references
(https://code.google.com/p/chromium/codesearch#search/&q=%22find-in-page%20coo...)
that these coordinates are referred to without further explanation in all of the
places they are used. I'm not sure if it is worth changing the comment here.

+  virtual void ActivateNearestFindResult(float x, float y) = 0;
+
+  // Requests the rects of the current find matches from the renderers.

[ncarter (slow), 2016/04/06 19:08:03]

Could you document what |current_version| means, who generates them (do they
come from content or the embedder?) and what the semantics are?

[paulmeyer, 2016/04/07 17:36:15]

Done.

+  virtual void RequestFindMatchRects(int current_version) = 0;
 #elif defined(OS_MACOSX)
   // Allowing other views disables optimizations which assume that only a single
   // WebContents is present.