Make serialized navigation entry moveable.

This class is inserted into vectors and has slow-to-copy-but-fast-to-move
members so would benefit from being moveable.

It was also assignable which was generating large implicit inline operator=
implementations. This makes operator= explicit and out-of-line.

Uses C++11 syntax for member initialization.

Change-Id: Ie4c591b716f85197f30603ebaeec27ddfc7cb2d6
Reviewed-on: https://chromium-review.googlesource.com/677058Reviewed-by: Stefan Kuhne <skuhne@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504173}

components/sessions/core/serialized_navigation_entry.cc

@@ -22,17 +22,7 @@ const char kSearchTermsKey[] = "search_terms";
 // The previous referrer policy value corresponding to |Never|.
 const int kObsoleteReferrerPolicyNever = 2;
 
-SerializedNavigationEntry::SerializedNavigationEntry()
-    : index_(-1),
-      unique_id_(0),
-      transition_type_(ui::PAGE_TRANSITION_TYPED),
-      has_post_data_(false),
-      post_id_(-1),
-      is_overriding_user_agent_(false),
-      http_status_code_(0),
-      is_restored_(false),
-      blocked_state_(STATE_INVALID),
-      password_state_(PASSWORD_STATE_UNKNOWN) {
+SerializedNavigationEntry::SerializedNavigationEntry() {
   referrer_policy_ =
       SerializedNavigationDriver::Get()->GetDefaultReferrerPolicy();
 }
@@ -40,7 +30,21 @@ SerializedNavigationEntry::SerializedNavigationEntry()
 SerializedNavigationEntry::SerializedNavigationEntry(
     const SerializedNavigationEntry& other) = default;
 
-SerializedNavigationEntry::~SerializedNavigationEntry() {}
+SerializedNavigationEntry::SerializedNavigationEntry(
+    SerializedNavigationEntry&& other) noexcept {
+  // VC 2015 can't handle "noexcept = default" constructors. We want the
+  // noexcept to avoid copying in a vector, but don't want to copy everything,
+  // by hand, so fall on the default-generated move operator=.
+  operator=(std::move(other));
+}
+
+SerializedNavigationEntry::~SerializedNavigationEntry() = default;
+
+SerializedNavigationEntry& SerializedNavigationEntry::operator=(
+    const SerializedNavigationEntry& other) = default;
+
+SerializedNavigationEntry& SerializedNavigationEntry::operator=(
+    SerializedNavigationEntry&& other) = default;
 
 SerializedNavigationEntry SerializedNavigationEntry::FromSyncData(
     int index,

components/sessions/core/serialized_navigation_entry.h

@@ -60,8 +60,12 @@ class SESSIONS_EXPORT SerializedNavigationEntry {
   // Creates an invalid (index < 0) SerializedNavigationEntry.
   SerializedNavigationEntry();
   SerializedNavigationEntry(const SerializedNavigationEntry& other);
+  SerializedNavigationEntry(SerializedNavigationEntry&& other) noexcept;
   ~SerializedNavigationEntry();
 
+  SerializedNavigationEntry& operator=(const SerializedNavigationEntry& other);
+  SerializedNavigationEntry& operator=(SerializedNavigationEntry&& other);
+
   // Construct a SerializedNavigationEntry for a particular index from a sync
   // protocol buffer.  Note that the sync protocol buffer doesn't contain all
   // SerializedNavigationEntry fields.  Also, the timestamp of the returned
@@ -155,32 +159,32 @@ class SESSIONS_EXPORT SerializedNavigationEntry {
   friend class IOSSerializedNavigationDriver;
 
   // Index in the NavigationController.
-  int index_;
+  int index_ = -1;
 
   // Member variables corresponding to NavigationEntry fields.
   // If you add a new field that can allocate memory, please also add
   // it to the EstimatedMemoryUsage() implementation.
-  int unique_id_;
+  int unique_id_ = 0;
   GURL referrer_url_;
   int referrer_policy_;
   GURL virtual_url_;
   base::string16 title_;
   std::string encoded_page_state_;
-  ui::PageTransition transition_type_;
-  bool has_post_data_;
-  int64_t post_id_;
+  ui::PageTransition transition_type_ = ui::PAGE_TRANSITION_TYPED;
+  bool has_post_data_ = false;
+  int64_t post_id_ = -1;
   GURL original_request_url_;
-  bool is_overriding_user_agent_;
+  bool is_overriding_user_agent_ = false;
   base::Time timestamp_;
   base::string16 search_terms_;
   GURL favicon_url_;
-  int http_status_code_;
-  bool is_restored_;    // Not persisted.
+  int http_status_code_ = 0;
+  bool is_restored_ = false;          // Not persisted.
   std::vector<GURL> redirect_chain_;  // Not persisted.
 
   // Additional information.
-  BlockedState blocked_state_;
-  PasswordState password_state_;
+  BlockedState blocked_state_ = STATE_INVALID;
+  PasswordState password_state_ = PASSWORD_STATE_UNKNOWN;
   std::set<std::string> content_pack_categories_;
 
   // Provides storage for arbitrary key/value pairs used by features. This