Converts parts of ios/web to ARC

ios/web/navigation/crw_session_controller.mm

Index: ios/web/navigation/crw_session_controller.mm
diff --git a/ios/web/navigation/crw_session_controller.mm b/ios/web/navigation/crw_session_controller.mm
index 85938fc01aff0d57368e09a92d71d18613ace9aa..c5078c9d9e8d4d4df37908eaf4af2722133887ab 100644
--- a/ios/web/navigation/crw_session_controller.mm
+++ b/ios/web/navigation/crw_session_controller.mm
@@ -12,7 +12,7 @@
 
 #include "base/format_macros.h"
 #include "base/logging.h"
-#include "base/mac/objc_property_releaser.h"
+#import "base/mac/foundation_util.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/metrics/user_metrics.h"
 #include "base/metrics/user_metrics_action.h"
@@ -30,6 +30,10 @@
 #include "ios/web/public/referrer.h"
 #include "ios/web/public/ssl_status.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 using base::UserMetricsAction;
 
 namespace {
@@ -102,8 +106,6 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
 
   // XCallback parameters used to create (or clobber) the tab. Can be nil.
   XCallbackParameters* _xCallbackParameters;
-
-  base::mac::ObjCPropertyReleaser _propertyReleaser_CRWSessionController;
 }
 
 // Redefine as readwrite.
@@ -111,9 +113,9 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
 
 // TODO(rohitrao): These properties must be redefined readwrite to work around a
 // clang bug. crbug.com/228650
-@property(nonatomic, readwrite, retain) NSString* tabId;
-@property(nonatomic, readwrite, retain) NSArray* entries;
-@property(nonatomic, readwrite, retain)
+@property(nonatomic, readwrite, copy) NSString* tabId;
+@property(nonatomic, readwrite, strong) NSArray* entries;
+@property(nonatomic, readwrite, strong)
     CRWSessionCertificatePolicyManager* sessionCertificatePolicyManager;
 
 - (NSString*)uniqueID;
@@ -153,15 +155,13 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
             browserState:(web::BrowserState*)browserState {
   self = [super init];
   if (self) {
-    _propertyReleaser_CRWSessionController.Init(self,
-                                                [CRWSessionController class]);
     self.windowName = windowName;
-    _tabId = [[self uniqueID] retain];
+    _tabId = [[self uniqueID] copy];
     _openerId = [openerId copy];
     _openedByDOM = openedByDOM;
     _openerNavigationIndex = openerIndex;
     _browserState = browserState;
-    _entries = [[NSMutableArray array] retain];
+    _entries = [NSMutableArray array];
     _lastVisitedTimestamp = [[NSDate date] timeIntervalSince1970];
     _currentNavigationIndex = -1;
     _previousNavigationIndex = -1;
@@ -176,9 +176,7 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
                  browserState:(web::BrowserState*)browserState {
   self = [super init];
   if (self) {
-    _propertyReleaser_CRWSessionController.Init(self,
-                                                [CRWSessionController class]);
-    _tabId = [[self uniqueID] retain];
+    _tabId = [[self uniqueID] copy];
     _openerId = nil;
     _browserState = browserState;
 
@@ -211,14 +209,12 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
 - (id)initWithCoder:(NSCoder*)aDecoder {
   self = [super init];
   if (self) {
-    _propertyReleaser_CRWSessionController.Init(self,
-                                                [CRWSessionController class]);
     NSString* uuid = [aDecoder decodeObjectForKey:kTabIdKey];
     if (!uuid)
       uuid = [self uniqueID];
 
     self.windowName = [aDecoder decodeObjectForKey:kWindowNameKey];
-    _tabId = [uuid retain];
+    _tabId = [uuid copy];
     _openerId = [[aDecoder decodeObjectForKey:kOpenerIdKey] copy];
     _openedByDOM = [aDecoder decodeBoolForKey:kOpenedByDOMKey];
     _openerNavigationIndex =
@@ -232,19 +228,19 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
     NSMutableArray* temp =
         [NSMutableArray arrayWithArray:
             [aDecoder decodeObjectForKey:kEntriesKey]];
-    _entries = [temp retain];
+    _entries = temp;
     // Prior to M34, 0 was used as "no index" instead of -1; adjust for that.
     if (![_entries count])
       _currentNavigationIndex = -1;
     _sessionCertificatePolicyManager =
-       [[aDecoder decodeObjectForKey:kCertificatePolicyManagerKey] retain];
+        [aDecoder decodeObjectForKey:kCertificatePolicyManagerKey];
     if (!_sessionCertificatePolicyManager) {
       _sessionCertificatePolicyManager =
           [[CRWSessionCertificatePolicyManager alloc] init];
     }
 
     _xCallbackParameters =
-        [[aDecoder decodeObjectForKey:kXCallbackParametersKey] retain];
+        [aDecoder decodeObjectForKey:kXCallbackParametersKey];
   }
   return self;
 }
@@ -268,8 +264,6 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
 
 - (id)copyWithZone:(NSZone*)zone {
   CRWSessionController* copy = [[[self class] alloc] init];
-  copy->_propertyReleaser_CRWSessionController.Init(
-      copy, [CRWSessionController class]);
   copy->_tabId = [_tabId copy];
   copy->_openerId = [_openerId copy];
   copy->_openedByDOM = _openedByDOM;
@@ -282,7 +276,8 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
       [[NSMutableArray alloc] initWithArray:_entries copyItems:YES];
   copy->_sessionCertificatePolicyManager =
       [_sessionCertificatePolicyManager copy];
-  copy->_xCallbackParameters = [_xCallbackParameters copy];
+  copy->_xCallbackParameters = [base::mac::ObjCCastStrict<NSObject<NSCopying>>(
+      _xCallbackParameters) copy];
   return copy;
 }
 
@@ -401,11 +396,11 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
       (self.currentEntry.navigationItem &&
        self.currentEntry.navigationItem->IsOverridingUserAgent());
   _useDesktopUserAgentForNextPendingEntry = NO;
-  _pendingEntry.reset([[self sessionEntryWithURL:url
-                                        referrer:ref
-                                      transition:trans
-                             useDesktopUserAgent:useDesktopUserAgent
-                               rendererInitiated:rendererInitiated] retain]);
+  _pendingEntry.reset([self sessionEntryWithURL:url
+                                       referrer:ref
+                                     transition:trans
+                            useDesktopUserAgent:useDesktopUserAgent
+                              rendererInitiated:rendererInitiated]);

[kkhorimoto, 2016/08/19 23:15:43]

How do scoped_nsobjects work within an ARC context?  The class expects to
receive an object with a +1 retainCount for calls to reset(), and the session
entry factory method here creates an autoreleased object.

Moreover, why are we using scoped_nsobject backing ivars at all post-ARC? 
Couldn't we just use a synthesized setter for |pendingEntry|?  Using
scoped_nsobjects to manage memory in an ARC environment is pretty confusing.

[stkhapugin, 2016/08/22 11:37:00]

As I said in design docs, PSAs and the lightning talk, scoped_nsobject and
WeakNSObject are correctly functioning with ARC. They are not going to be
rewritten to __strong and __weak in the first round of CLs to keep the code
reviews sanely sized and the flag-flipping process faster. In ARC files, you can
write new code without scoped pointers if you wish.

The process for removing scoped_nsobject/WeakNSObject is mostly there, but will
generate much more code reviews. It is probably going to wait until everything
in ios/ is built with ARC.

 
   if (_navigationManager && _navigationManager->GetFacadeDelegate()) {
     _navigationManager->GetFacadeDelegate()->OnNavigationItemPending();
@@ -454,7 +449,7 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
   // Store removed items in temporary NSArray so they can be deallocated after
   // their facades.
   base::scoped_nsobject<NSArray> removedItems(
-      [[_entries subarrayWithRange:remove] retain]);
+      [_entries subarrayWithRange:remove]);
   [_entries removeObjectsInRange:remove];
   if (_previousNavigationIndex >= forwardEntryStartIndex)
     _previousNavigationIndex = -1;
@@ -487,12 +482,12 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
 }
 
 - (void)addTransientEntryWithURL:(const GURL&)URL {
-  _transientEntry.reset(
-      [[self sessionEntryWithURL:URL
-                        referrer:web::Referrer()
-                      transition:ui::PAGE_TRANSITION_CLIENT_REDIRECT
-             useDesktopUserAgent:NO
-               rendererInitiated:NO] retain]);
+  _transientEntry.reset([self
+      sessionEntryWithURL:URL
+                 referrer:web::Referrer()
+               transition:ui::PAGE_TRANSITION_CLIENT_REDIRECT
+      useDesktopUserAgent:NO
+        rendererInitiated:NO]);
 
   web::NavigationItem* navigationItem = [_transientEntry navigationItem];
   DCHECK(navigationItem);
@@ -510,12 +505,12 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
   web::Referrer referrer(item->GetURL(), web::ReferrerPolicyDefault);
   bool overrideUserAgent =
       self.currentEntry.navigationItem->IsOverridingUserAgent();
-  base::scoped_nsobject<CRWSessionEntry> pushedEntry(
-      [[self sessionEntryWithURL:URL
-                        referrer:referrer
-                      transition:transition
-             useDesktopUserAgent:overrideUserAgent
-               rendererInitiated:NO] retain]);
+  base::scoped_nsobject<CRWSessionEntry> pushedEntry([self
+      sessionEntryWithURL:URL
+                 referrer:referrer
+               transition:transition
+      useDesktopUserAgent:overrideUserAgent
+        rendererInitiated:NO]);
   web::NavigationItemImpl* pushedItem = [pushedEntry navigationItemImpl];
   pushedItem->SetSerializedStateObject(stateObject);
   pushedItem->SetIsCreatedFromPushState(true);
@@ -556,7 +551,6 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
   // entry; since navigations clear the transient entry, these flows might
   // crash. (This should be removable once more session management is handled
   // within this class and/or NavigationManager).
-  [[_transientEntry retain] autorelease];
   _transientEntry.reset();
 }
 
@@ -572,8 +566,8 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
     self.currentNavigationIndex = -1;
     _previousNavigationIndex = -1;
   }
-  self.xCallbackParameters =
-      [[otherSession.xCallbackParameters copy] autorelease];
+  self.xCallbackParameters = [base::mac::ObjCCastStrict<NSObject<NSCopying>>(
+      otherSession.xCallbackParameters) copy];
   self.windowName = otherSession.windowName;
   NSInteger numInitialEntries = [_entries count];
 
@@ -849,9 +843,9 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
 - (NSString*)uniqueID {
   CFUUIDRef uuidRef = CFUUIDCreate(NULL);
   CFStringRef uuidStringRef = CFUUIDCreateString(NULL, uuidRef);
-  CFRelease(uuidRef);
-  NSString* uuid = [NSString stringWithString:(NSString*)uuidStringRef];
-  CFRelease(uuidStringRef);
+  NSString* uuid =
+      [NSString stringWithString:base::mac::ObjCCastStrict<NSString>(
+                                     CFBridgingRelease(uuidStringRef))];
   return uuid;
 }
 
@@ -880,8 +874,7 @@ NSString* const kXCallbackParametersKey = @"xCallbackParameters";
   item->SetTransitionType(transition);
   item->SetIsOverridingUserAgent(useDesktopUserAgent);
   item->set_is_renderer_initiated(rendererInitiated);
-  return [[[CRWSessionEntry alloc] initWithNavigationItem:std::move(item)]
-      autorelease];
+  return [[CRWSessionEntry alloc] initWithNavigationItem:std::move(item)];
 }
 
 @end