Upstream Chrome on iOS source code [2/11].

ios/chrome/browser/snapshots/web_controller_snapshot_helper.h

+// Copyright 2014 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_CHROME_BROWSER_SNAPSHOTS_WEB_CONTROLLER_SNAPSHOT_HELPER_H_
+#define IOS_CHROME_BROWSER_SNAPSHOTS_WEB_CONTROLLER_SNAPSHOT_HELPER_H_
+
+#import <UIKit/UIKit.h>
+
+@class CRWWebController;
+@class SnapshotManager;
+@class Tab;
+
+// A class that takes care of creating, storing and returning snapshots of a
+// WebController's web page.
+// TODO(crbug.com/661642): There is a lot of overlap/common functionality
+// between this class and SnapshotManager, coalesce these 2 classes.
+@interface WebControllerSnapshotHelper : NSObject
+
+// Designated initializer. |snapshotManager|, |sessionID|, |webController|
+// should not be nil.
+// TODO(crbug.com/661641): Since we already retain a CRWWebController* and that
+// is the  same which is passed to these methods, remove the CRWWebController
+// param from the following methods.
+// TODO(crbug.com/380819): Replace the need to use Tab directly here by using a
+// delegate pattern.
+- (instancetype)initWithSnapshotManager:(SnapshotManager*)snapshotManager
+                                    tab:(Tab*)tab;
+
+// If |snapshotCoalescingEnabled| is YES snapshots of the web page are
+// coalesced until this method is called with |snapshotCoalescingEnabled| set to
+// NO. When snapshot coalescing is enabled, mutiple calls to generate a snapshot
+// with the same parameters may be coalesced.
+- (void)setSnapshotCoalescingEnabled:(BOOL)snapshotCoalescingEnabled;
+
+// Gets a color snapshot for the WebController's page, calling |callback| if it
+// is found. |overlays| is the array of SnapshotOverlay objects (views currently
+// overlayed), can be nil.
+- (void)retrieveSnapshotForWebController:(CRWWebController*)webController
+                               sessionID:(NSString*)sessionID
+                            withOverlays:(NSArray*)overlays
+                                callback:(void (^)(UIImage* image))callback;
+
+// Gets a grey snapshot for the webController's current page, calling |callback|
+// if it is found. |overlays| is the array of SnapshotOverlay objects
+// (views currently overlayed), can be nil.
+- (void)retrieveGreySnapshotForWebController:(CRWWebController*)webController
+                                   sessionID:(NSString*)sessionID
+                                withOverlays:(NSArray*)overlays
+                                    callback:(void (^)(UIImage* image))callback;
+
+// Invalidates the cached snapshot for the controller's current session and
+// forces a more recent snapshot to be generated and stored. Returns the
+// snapshot with or without the overlayed views (e.g. infobar, voice search
+// button, etc.), and either of the visible frame or of the full screen.
+// |overlays| is the array of SnapshotOverlay objects (views currently
+// overlayed), can be nil.
+- (UIImage*)updateSnapshotForWebController:(CRWWebController*)webController
+                                 sessionID:(NSString*)sessionID
+                              withOverlays:(NSArray*)overlays
+                          visibleFrameOnly:(BOOL)visibleFrameOnly;
+
+// Takes a snapshot image for the current page including optional infobars.
+// Returns an autoreleased image cropped and scaled appropriately, with or
+// without the overlayed views (e.g. infobar, voice search button, etc.), and
+// either of the visible frame or of the full screen.
+// Returns nil if a snapshot cannot be generated.
+// |overlays| is the array of SnapshotOverlay objects (views currently
+// overlayed), can be nil.
+- (UIImage*)generateSnapshotForWebController:(CRWWebController*)webController
+                                withOverlays:(NSArray*)overlays
+                            visibleFrameOnly:(BOOL)visibleFrameOnly;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_SNAPSHOTS_WEB_CONTROLLER_SNAPSHOT_HELPER_H_