[iOS] Upstream //ios/chrome/browser/memory

ios/chrome/browser/memory/memory_debugger_manager.mm

+// 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.
+
+#import "ios/chrome/browser/memory/memory_debugger_manager.h"
+
+#include "base/ios/weak_nsobject.h"
+#import "base/mac/bind_objc_block.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/prefs/pref_member.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_service.h"
+#import "ios/chrome/browser/memory/memory_debugger.h"
+#import "ios/chrome/browser/pref_names.h"
+
+@implementation MemoryDebuggerManager {
+  UIView* debuggerParentView_;  // weak
+  base::scoped_nsobject<MemoryDebugger> memoryDebugger_;
+  BooleanPrefMember showMemoryDebugger_;
+}
+
+- (instancetype)initWithView:(UIView*)debuggerParentView
+                       prefs:(PrefService*)prefs {
+  if (self = [super init]) {
+    debuggerParentView_ = debuggerParentView;
+
+    // Set up the callback for when the pref to show/hide the debugger changes.
+    base::WeakNSObject<MemoryDebuggerManager> weakSelf(self);
+    base::Closure callback = base::BindBlock(^{
+      base::scoped_nsobject<MemoryDebuggerManager> strongSelf(
+          [weakSelf retain]);
+      if (strongSelf) {
+        [self onShowMemoryDebuggingToolsChange];
+      }
+    });
+    showMemoryDebugger_.Init(prefs::kShowMemoryDebuggingTools, prefs, callback);
+    // Invoke the pref change callback once to show the debugger on start up,
+    // if necessary.
+    [self onShowMemoryDebuggingToolsChange];
+  }
+  return self;
+}
+
+- (void)dealloc {
+  [self tearDownDebugger];
+  [super dealloc];
+}
+
+#pragma mark - Pref-handling methods
+
+// Registers local state prefs.
++ (void)registerLocalState:(PrefRegistrySimple*)registry {
+  registry->RegisterBooleanPref(prefs::kShowMemoryDebuggingTools, false);
+}
+
+// Shows or hides the debugger when the pref changes.
+- (void)onShowMemoryDebuggingToolsChange {
+  if (showMemoryDebugger_.GetValue()) {
+    memoryDebugger_.reset([[MemoryDebugger alloc] init]);
+    [debuggerParentView_ addSubview:memoryDebugger_];
+  } else {
+    [self tearDownDebugger];
+  }
+}
+
+// Tears down the debugger so it can be deallocated.
+- (void)tearDownDebugger {
+  [memoryDebugger_ invalidateTimers];
+  [memoryDebugger_ removeFromSuperview];
+  memoryDebugger_.reset();
+}
+@end