Add ProvisionalNavigationStarted to WebStateObserver

Adds ProvisionalNavigationStarted to WebStateObserver.
ProvisionalNavigationStarted is invokes when a load request is
registered. It will be used to detect provisional page loads for
intercepting WebUI requests.

BUG=450362

Review URL: https://codereview.chromium.org/1097363002

Cr-Commit-Position: refs/heads/master@{#326086}

3 files changed, 16 insertions, 0 deletions

diff --git a/ios/web/public/web_state/web_state_observer.h b/ios/web/public/web_state/web_state_observer.h
index cd254f8..c24e299 100644
--- a/ios/web/public/web_state/web_state_observer.h
+++ b/ios/web/public/web_state/web_state_observer.h
@@ -32,6 +32,9 @@ class WebStateObserver {
   // Returns the web state associated with this observer.
   WebState* web_state() const { return web_state_; }
 
+  // This method is invoked when a load request is registered.
+  virtual void ProvisionalNavigationStarted(const GURL& url) {}
+
   // This method is invoked when a new non-pending navigation item is created.
   // This corresponds to one NavigationManager item being created
   // (in the case of new navigations) or renavigated to (for back/forward
diff --git a/ios/web/public/web_state/web_state_observer_bridge.h b/ios/web/public/web_state/web_state_observer_bridge.h
index bc34bd6..e61bea441 100644
--- a/ios/web/public/web_state/web_state_observer_bridge.h
+++ b/ios/web/public/web_state/web_state_observer_bridge.h
@@ -18,6 +18,11 @@ class GURL;
 // web::WebStateObserver, wrap in a web::WebStateObserverBridge.
 @protocol CRWWebStateObserver<NSObject>
 @optional
+
+// Invoked by WebStateObserverBridge::ProvisionalNavigationStarted.
+- (void)webState:(web::WebState*)webState
+    didStartProvisionalNavigationForURL:(const GURL&)URL;
+
 // Invoked by WebStateObserverBridge::NavigationItemCommitted.
 - (void)webState:(web::WebState*)webState
     didCommitNavigationWithDetails:
@@ -82,6 +87,7 @@ class WebStateObserverBridge : public web::WebStateObserver {
   ~WebStateObserverBridge() override;
 
   // web::WebStateObserver methods.
+  void ProvisionalNavigationStarted(const GURL& url) override;
   void NavigationItemCommitted(
       const LoadCommittedDetails& load_details) override;
   void PageLoaded(
diff --git a/ios/web/web_state/web_state_observer_bridge.mm b/ios/web/web_state/web_state_observer_bridge.mm
index eef1be7..c2028fe 100644
--- a/ios/web/web_state/web_state_observer_bridge.mm
+++ b/ios/web/web_state/web_state_observer_bridge.mm
@@ -14,6 +14,13 @@ WebStateObserverBridge::WebStateObserverBridge(web::WebState* webState,
 WebStateObserverBridge::~WebStateObserverBridge() {
 }
 
+void WebStateObserverBridge::ProvisionalNavigationStarted(const GURL& url) {
+  SEL selector = @selector(webState:didStartProvisionalNavigationForURL:);
+  if ([observer_ respondsToSelector:selector]) {
+    [observer_ webState:web_state() didStartProvisionalNavigationForURL:url];
+  }
+}
+
 void WebStateObserverBridge::NavigationItemCommitted(
     const web::LoadCommittedDetails& load_detatils) {
   SEL selector = @selector(webState:didCommitNavigationWithDetails:);