[iOS] Ensure classes don’t retain injection receiver.

CRWJSInjectionReceiver shouldn’t be retained, except by CRWWebController. Update
other references to weak.

Bug: 1004321
Change-Id: I0c936b476fb65c8d1d2e0f0be6f5179257897aab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1807606
Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
Reviewed-by: Moe Ahmadi <mahmadi@chromium.org>
Reviewed-by: Vadym Doroshenko <dvadym@chromium.org>
Auto-Submit: Mike Dougherty <michaeldo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697248}

components/autofill/ios/browser/js_autofill_manager.mm

@@ -28,7 +28,7 @@
 
 @implementation JsAutofillManager {
   // The injection receiver used to evaluate JavaScript.
-  CRWJSInjectionReceiver* _receiver;
+  __weak CRWJSInjectionReceiver* _receiver;
 }
 
 - (instancetype)initWithReceiver:(CRWJSInjectionReceiver*)receiver {

components/autofill/ios/browser/js_suggestion_manager.mm

@@ -24,7 +24,7 @@
 
 @implementation JsSuggestionManager {
   // The injection receiver used to evaluate JavaScript.
-  CRWJSInjectionReceiver* _receiver;
+  __weak CRWJSInjectionReceiver* _receiver;
   web::WebFramesManager* _webFramesManager;
 }
 

components/password_manager/ios/js_password_manager.mm

@@ -75,7 +75,7 @@ NSString* JSONEscape(NSString* JSONString) {
 
 @implementation JsPasswordManager {
   // The injection receiver used to evaluate JavaScript.
-  CRWJSInjectionReceiver* _receiver;
+  __weak CRWJSInjectionReceiver* _receiver;
 }
 
 - (instancetype)initWithReceiver:(CRWJSInjectionReceiver*)receiver {