Begin abstracting sending of IPC from autofill core code.

components/autofill/core/browser/autofill_driver.h

Index: components/autofill/core/browser/autofill_driver.h
diff --git a/components/autofill/core/browser/autofill_driver.h b/components/autofill/core/browser/autofill_driver.h
index 178e31b98b83682392d6e0760b691028eedac94f..8b92ded91c17d6e7541a059b40161dab6e735d92 100644
--- a/components/autofill/core/browser/autofill_driver.h
+++ b/components/autofill/core/browser/autofill_driver.h
@@ -5,14 +5,17 @@
 #ifndef COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_DRIVER_H_
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_DRIVER_H_
 
+#include "components/autofill/core/common/form_data.h"
+
 namespace content {
 class WebContents;
 }
 
 namespace autofill {
 
-// Interface that provides access to the driver-level context in which Autofill
-// is operating. A concrete implementation must be provided by the driver.
+// Interface that allows Autofill core code to interact with its driver (i.e.,
+// obtain information from it and give information to it). A concrete
+// implementation must be provided by the driver.
 class AutofillDriver {
  public:
   virtual ~AutofillDriver() {}
@@ -20,6 +23,13 @@ class AutofillDriver {
   // TODO(blundell): Remove this method once shared code no longer needs to
   // know about WebContents.
   virtual content::WebContents* GetWebContents() = 0;
+
+  // Returns true iff the renderer is available for communication.
+  virtual bool CanSendToRenderer() = 0;

[Ilya Sherman, 2013/06/25 01:22:33]

Would it make more sense for SendFormDataToRenderer() to return a boolean, or
perhaps for the client to simply fire-and-forget, without needing to worry about
this at all?  Or are there times when the client would want to know whether it's
possible to communicate with the renderer, but then not actually go ahead and
send a message over?

[blundell, 2013/06/25 16:11:04]

I noticed a couple places where there's a short-circuit out of a method, most
significantly in AutofillManager::OnFormsSeen(). But you're right that most of
the time the core code doesn't care. Changed SendFormDataToRenderer() to be a
no-op if the renderer isn't available.

On 2013/06/25 01:22:33, Ilya Sherman wrote:

+
+  // Forwards |data| to the renderer. |query_id| is the id of the renderer's
+  // original request for the data.
+  virtual void SendFormDataToRenderer(int query_id, FormData data) = 0;
 };
 
 }  // namespace autofill