[ios] Adds support for Find in Page to the new architecture.

ios/clean/chrome/browser/browser_coordinator.mm

Index: ios/clean/chrome/browser/browser_coordinator.mm
diff --git a/ios/clean/chrome/browser/browser_coordinator.mm b/ios/clean/chrome/browser/browser_coordinator.mm
index 828ae8d4f6c66cd4e69feb3565c4e17be8c95f16..baf124e91973d53bea63c6869f6c69ff8bf46332 100644
--- a/ios/clean/chrome/browser/browser_coordinator.mm
+++ b/ios/clean/chrome/browser/browser_coordinator.mm
@@ -68,6 +68,7 @@
   coordinator.parentCoordinator = self;
   coordinator.browser = self.browser;
   coordinator.context.baseViewController = self.viewController;
+  [coordinator coordinatorDidMoveToParent:self];

[rohitrao (ping after 24h), 2017/03/14 01:10:36]

1) I found a need for a "didMoveToParent" method.  The FIP coordinator needs a
Browser (WebStateList and CommandDispatcher) in order to really initialize
itself.  It doesn't have one yet in |-init|, and |-start| is too late given that
coordinators may never be started under our new design.

I actually think that most coordinators will do nothing in init, but that seems
ok.

 }
 
 - (BrowserCoordinator*)overlayCoordinator {
@@ -122,6 +123,10 @@
   coordinator.parentCoordinator = nil;
 }
 
+- (void)coordinatorDidMoveToParent:(BrowserCoordinator*)parentCoordinator {
+  // Default implementation is a no-op.
+}
+
 - (void)childCoordinatorDidStart:(BrowserCoordinator*)childCoordinator {
   // Default implementation is a no-op.
 }