Upstream JavaScript injection for iOS

ios/web/public/web_state/js/crw_js_injection_evaluator.h

Index: ios/web/public/web_state/js/crw_js_injection_evaluator.h
diff --git a/ios/web/public/web_state/js/crw_js_injection_evaluator.h b/ios/web/public/web_state/js/crw_js_injection_evaluator.h
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index 0000000000000000000000000000000000000000..724f1bdfa061bf2a72418ba559784a14eed525f6
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+++ b/ios/web/public/web_state/js/crw_js_injection_evaluator.h
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+// Copyright 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IOS_WEB_PUBLIC_WEB_STATE_JS_CRW_JS_INJECTION_EVALUATOR_H_
+#define IOS_WEB_PUBLIC_WEB_STATE_JS_CRW_JS_INJECTION_EVALUATOR_H_
+
+#import <Foundation/Foundation.h>
+
+// The type of the completion handler block that is called from
+// |evaluateJavaScript:completionHandler|
+namespace web {
+typedef void (^JavaScriptCompletion)(NSString*, NSError*);
+}
+
+@protocol CRWJSInjectionEvaluator
+
+// Evaluates the supplied JavaScript in the WebView. Calls |completionHandler|
+// with results of the evaluation (which may be nil if the implementing object
+// has no way to run the evaluation or the evaluation returns a nil value)
+// or an NSError if there is an error. The |completionHandler| can be nil.
+- (void)evaluateJavaScript:(NSString*)script
+       stringResultHandler:(web::JavaScriptCompletion)handler;
+
+// Checks to see if the script for a class has been injected into the
+// current page already, given the class and the script's presence
+// beacon (a JS object that should exist iff the script has been injected).
+- (BOOL)scriptHasBeenInjectedForClass:(Class)jsInjectionManagerClass
+                       presenceBeacon:(NSString*)beacon;
+
+// Injects the given script into the current page on behalf of
+// |jsInjectionManagerClass|. This should only be used for injecting
+// the manager's script, and not for evaluating arbitrary JavaScript.
+- (void)injectScript:(NSString*)script forClass:(Class)jsInjectionManagerClass;
+
+@end
+
+#endif  // IOS_WEB_PUBLIC_WEB_STATE_JS_CRW_JS_INJECTION_EVALUATOR_H_