[ios] Remove Contextual Search code from the BVC.

This CL removes all contextual search code from the BVC. Almost all of
the logic contained in the BVC is ported to a new wrangler class.

Any object wishing to use contextual search (without further refactoring)
will need to furnish a provider object as defined in the wrangler class
header, which at this stage just encapsulates all of the interfaces into
the BVC that the contextual search code used to use.

Bug: 
Change-Id: I23ffe787b26ead87c9c50e4730851f6b992c95a4
Reviewed-on: https://chromium-review.googlesource.com/574534
Commit-Queue: Mark Cogan <marq@chromium.org>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487435}

ios/chrome/browser/ui/BUILD.gn

@@ -258,7 +258,6 @@ source_set("ui_internal_arc") {
     "//ios/chrome/browser/ui/colors",
     "//ios/chrome/browser/ui/commands",
     "//ios/chrome/browser/ui/context_menu",
-    "//ios/chrome/browser/ui/contextual_search",
     "//ios/chrome/browser/ui/dialogs:dialogs_internal",
     "//ios/chrome/browser/ui/elements:elements_internal",
     "//ios/chrome/browser/ui/find_bar",

ios/chrome/browser/ui/contextual_search/BUILD.gn

@@ -46,6 +46,8 @@ source_set("contextual_search") {
     "contextual_search_results_view.mm",
     "contextual_search_web_state_observer.h",
     "contextual_search_web_state_observer.mm",
+    "contextual_search_wrangler.h",
+    "contextual_search_wrangler.mm",
     "js_contextual_search_manager.h",
     "js_contextual_search_manager.mm",
     "panel_configuration.h",

ios/chrome/browser/ui/contextual_search/contextual_search_wrangler.h

+// Copyright 2017 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_UI_CONTEXTUAL_SEARCH_CONTEXTUAL_SEARCH_WRANGLER_H_
+#define IOS_CHROME_BROWSER_UI_CONTEXTUAL_SEARCH_CONTEXTUAL_SEARCH_WRANGLER_H_
+
+#import <UIKit/UIKit.h>
+
+namespace ios {
+class ChromeBrowserState;
+}
+@class Tab;
+@class TabModel;
+
+// A provider protocol for Contextual Search; this defines all of the things
+// that the Contextual Search system needs to be able to ask for from or change
+// in the application as a whole.
+@protocol ContextualSearchProvider<NSObject>
+
+// The parent view that the contextual search panel will be a subview of.
+@property(nonatomic, readonly) UIView* view;
+
+// The view (if any) containing the tab strip. This may be used for height
+// calculations for positioning or aninmating the contextual search view.
+@property(nonatomic, readonly) UIView* tabStripView;
+
+// The view containing the toolbar. This should be a subview of the view
+// exposed in |view|, above. The contextual search panel will be
+// positioned in front of this view, and the contexual search mask will be
+// positioned behind it (in the z-axis).
+@property(nonatomic, readonly) UIView* toolbarView;
+
+// Tells the provider to set the toolbar control alpha.
+- (void)updateToolbarControlsAlpha:(CGFloat)alpha;
+
+// Tells the provider to set the toolbar background alpha.
+- (void)updateToolbarBackgroundAlpha:(CGFloat)alpha;
+
+// Tell the provider that a tab load inside contextual search has completed.
+// |tab| is that tab that has loaded, and |sucess| is YES if the tab loaded
+// without error, and NO otherwise.
+- (void)tabLoadComplete:(Tab*)tab withSuccess:(BOOL)success;
+
+// Tells the pr=ovider to focus the omnibox.
+- (void)focusOmnibox;
+
+// Tells the provider to restore any suspended infobars.
+- (void)restoreInfobars;
+
+// Tells the provider to suspend any infobars..
+- (void)suspendInfobars;
+
+// Asks the provider for the current header offset for positinioning the panel.
+- (CGFloat)currentHeaderOffset;
+
+@end
+
+// An object that manages the interactions of the contextual search system with
+// the rest of teh application. An instance of this object handles creating and
+// positioning all of the views required for contextual search, as well as all
+// of the other controller objects.
+@interface ContextualSearchWrangler : NSObject
+
+// Creates a new wrangler object for |provider| and |tabModel|.
+- (instancetype)initWithProvider:(id<ContextualSearchProvider>)provider
+                        tabModel:(TabModel*)tabModel NS_DESIGNATED_INITIALIZER;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+// Inserts the panel view into the view hierarchy provided by the provider the
+// receiver was initialized with.
+- (void)insertPanelView;
+
+// Starts contextual search using the reciever for |browserState|. This should
+// only be called once in the lifetime of the receiver. If it is possible
+// (as determined by TouchToSearchPermissionsMediator) to start contextual
+// search on this device, and |browserState| isn't incognito, then this method
+// will create the contextual search controller objects and views and start
+// observing the tab model it was initialized with.
+- (void)maybeStartForBrowserState:(ios::ChromeBrowserState*)browserState;
+
+// Enables or disables contextual search for the reciever; this may be called
+// multiple times during the lifetime of the receiver.
+- (void)enable:(BOOL)enabled;
+
+// Tears down the controller and views the receiver has created. This method
+// must be called before the receiver is deallocated.
+- (void)stop;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_CONTEXTUAL_SEARCH_CONTEXTUAL_SEARCH_WRANGLER_H_