Blink class layout optimization to reduce memory usage

Blink class layout optimization to reduce memory usage

This change optimizes class layout on 64-bit in 4 blink classes, all
related to images. Considering the 16 bit allocation granularity
this saves 16 bytes per instance of each class. It looks like a
typical web page might have up to a few hundred instances of each
class so the total memory saving ~ 16-32 KB per Renderer process,
potentially more for image heavy pages.

UPDATE: crrev.com/2746343002 added a new field to ImageResourceContent
which further increased it size by 8 bytes. I've moved the fields
around again to still make it squeeze into 80 bytes.

Layout details:

Before:
    class blink::Image [sizeof = 40]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8] 
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      <padding> (4 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver> image_observer_
      data +0x20 [sizeof=1] bool image_observer_disabled_
      <padding> (7 bytes)
    }

After:
   class blink::Image [sizeof = 32]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8]
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      data +0x0c [sizeof=1] bool image_observer_disabled_
      <padding> (3 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver> image_observer_
    }

Before:
    class blink::BitmapImage [sizeof = 280]
      : public blink::Image {
      base +0x00 [sizeof=33] blink::Image
      <padding> (7 bytes)
      data +0x28 [sizeof=112] blink::ImageSource source_
      data +0x98 [sizeof=8] blink::IntSize size_
      data +0xa0 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa8 [sizeof=8] unsigned __int64 current_frame_
      data +0xb0 [sizeof=40] WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd8 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xe0 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe8 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] blink::BitmapImage::RepetitionCountStatus repetition_count_status_
      data +0xf8 [sizeof=4] int repetitions_complete_
      <padding> (4 bytes)
      data +0x100 [sizeof=8] double desired_frame_start_time_
      data +0x108 [sizeof=8] unsigned __int64 frame_count_
      data +0x110 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0x114 [sizeof=1] bool animation_finished_ : 1
      data +0x114 [sizeof=1] bool all_data_received_ : 1
      data +0x114 [sizeof=1] bool have_size_ : 1
      data +0x114 [sizeof=1] bool size_available_ : 1
      data +0x114 [sizeof=1] bool have_frame_count_ : 1
      <padding> (3 bytes)
    }

After:
    class blink::BitmapImage [sizeof = 264]
      : public blink::Image {
      base +0x00 [sizeof=32] blink::Image
      data +0x20 [sizeof=112] blink::ImageSource source_
      data +0x90 [sizeof=8] blink::IntSize size_
      data +0x98 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa0 [sizeof=8] unsigned __int64 current_frame_
      data +0xa8 [sizeof=40] WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd0 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xd8 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe0 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xe8 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0xec [sizeof=1] bool animation_finished_ : 1
      data +0xec [sizeof=1] bool all_data_received_ : 1
      data +0xec [sizeof=1] bool have_size_ : 1
      data +0xec [sizeof=1] bool size_available_ : 1
      data +0xec [sizeof=1] bool have_frame_count_ : 1
      data +0xed [sizeof=1] blink::BitmapImage::RepetitionCountStatus repetition_count_status_
      <padding> (2 bytes)
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] int repetitions_complete_
      data +0xf8 [sizeof=8] double desired_frame_start_time_
      data +0x100 [sizeof=8] unsigned __int64 frame_count_
    }

Before:
    class blink::ImageResourceContent [sizeof = 96]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1] blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      <padding> (7 bytes)
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=4] blink::ResourceStatus content_status_
      <padding> (4 bytes)
      data +0x20 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x28 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x40 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
      data +0x58 [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x5C [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x5D [sizeof=1] bool is_add_remove_observer_prohibited_
      <padding> (2 bytes)
    }

After:
    class blink::ImageResourceContent [sizeof = 80]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1] blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      data +0x09 [sizeof=1] blink::ResourceStatus content_status_
      data +0x0a [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x0b [sizeof=1] bool is_add_remove_observer_prohibited_
      data +0x0c [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x20 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x38 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
    }

Before:
    class blink::DeferredImageDecoder [sizeof = 96] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=1] bool all_data_received_
      <padding> (7 bytes)
      data +0x10 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x18 [sizeof=8] WTF::String filename_extension_
      data +0x20 [sizeof=8] blink::IntSize size_
      data +0x28 [sizeof=4] int repetition_count_
      data +0x2c [sizeof=1] bool has_embedded_color_space_
      <padding> (3 bytes)
      data +0x30 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x38 [sizeof=1] bool can_yuv_decode_
      data +0x39 [sizeof=1] bool has_hot_spot_
      <padding> (2 bytes)
      data +0x3c [sizeof=8] blink::IntPoint hot_spot_
      <padding> (4 bytes)
      data +0x48 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x58 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }

After:
    class blink::DeferredImageDecoder [sizeof = 80] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x10 [sizeof=8] WTF::String filename_extension_
      data +0x18 [sizeof=8] blink::IntSize size_
      data +0x20 [sizeof=4] int repetition_count_
      data +0x24 [sizeof=1] bool has_embedded_color_space_
      data +0x25 [sizeof=1] bool all_data_received_
      data +0x26 [sizeof=1] bool can_yuv_decode_
      data +0x27 [sizeof=1] bool has_hot_spot_
      data +0x28 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x30 [sizeof=8] blink::IntPoint hot_spot_
      data +0x38 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x48 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }


BUG=710933
Review-Url: https://codereview.chromium.org/2859313003
Cr-Commit-Position: refs/heads/master@{#470373}
Committed: https://chromium.googlesource.com/chromium/src/+/4f54bee9b89dd593c338dbc684f806bb73b48256

[stanisc, 2017-05-05 18:13:22]

The CQ bit was checked by stanisc@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-05 18:14:10]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-05 18:33:28]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-05 18:33:29]

Dry run: Try jobs failed on following builders:
  linux_chromium_tsan_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)

[stanisc, 2017-05-05 18:36:33]

The CQ bit was checked by stanisc@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-05 18:37:11]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-05 21:00:53]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-05 21:00:55]

Dry run: Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[stanisc, 2017-05-05 21:07:24]

Description was changed from

==========
Blink class layout optimization

BUG=
==========

to

==========
Blink class layout optimization to reduce memory usage

This change optimizes class layout on 64-bit in 4 blink classes, all
related to images. Considering the 16 bit allocation granularity
this saves 16 bytes per instance of each class. It looks like a
typical web page might have up to a few hundred instances of each
class so the total memory saving ~ 16-32 KB per Renderer process,
potentially more for image heavy pages.

Layout details:

Before:
    class blink::Image [sizeof = 40]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8] 
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      <padding> (4 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
      data +0x20 [sizeof=1] bool image_observer_disabled_
      <padding> (7 bytes)
    }

After:
   class blink::Image [sizeof = 32]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8]
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      data +0x0c [sizeof=1] bool image_observer_disabled_
      <padding> (3 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
    }

Before:
    class blink::BitmapImage [sizeof = 280]
      : public blink::Image {
      base +0x00 [sizeof=33] blink::Image
      <padding> (7 bytes)
      data +0x28 [sizeof=112] blink::ImageSource source_
      data +0x98 [sizeof=8] blink::IntSize size_
      data +0xa0 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa8 [sizeof=8] unsigned __int64 current_frame_
      data +0xb0 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd8 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xe0 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe8 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      data +0xf8 [sizeof=4] int repetitions_complete_
      <padding> (4 bytes)
      data +0x100 [sizeof=8] double desired_frame_start_time_
      data +0x108 [sizeof=8] unsigned __int64 frame_count_
      data +0x110 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0x114 [sizeof=1] bool animation_finished_ : 1
      data +0x114 [sizeof=1] bool all_data_received_ : 1
      data +0x114 [sizeof=1] bool have_size_ : 1
      data +0x114 [sizeof=1] bool size_available_ : 1
      data +0x114 [sizeof=1] bool have_frame_count_ : 1
      <padding> (3 bytes)
    }

After:
    class blink::BitmapImage [sizeof = 264]
      : public blink::Image {
      base +0x00 [sizeof=32] blink::Image
      data +0x20 [sizeof=112] blink::ImageSource source_
      data +0x90 [sizeof=8] blink::IntSize size_
      data +0x98 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa0 [sizeof=8] unsigned __int64 current_frame_
      data +0xa8 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd0 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xd8 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe0 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xe8 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0xec [sizeof=1] bool animation_finished_ : 1
      data +0xec [sizeof=1] bool all_data_received_ : 1
      data +0xec [sizeof=1] bool have_size_ : 1
      data +0xec [sizeof=1] bool size_available_ : 1
      data +0xec [sizeof=1] bool have_frame_count_ : 1
      data +0xed [sizeof=1] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      <padding> (2 bytes)
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] int repetitions_complete_
      data +0xf8 [sizeof=8] double desired_frame_start_time_
      data +0x100 [sizeof=8] unsigned __int64 frame_count_
    }

Before:
    class blink::ImageResourceContent [sizeof = 88]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      <padding> (7 bytes)
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x20 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x38 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
      data +0x50 [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x54 [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x55 [sizeof=1] bool is_add_remove_observer_prohibited_
      <padding> (2 bytes)
    }

After:
    class blink::ImageResourceContent [sizeof = 80]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      data +0x09 [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x0a [sizeof=1] bool is_add_remove_observer_prohibited_
      <padding> (1 bytes)
      data +0x0c [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x20 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x38 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
    }

Before:
    class blink::DeferredImageDecoder [sizeof = 96] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=1] bool all_data_received_
      <padding> (7 bytes)
      data +0x10 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x18 [sizeof=8] WTF::String filename_extension_
      data +0x20 [sizeof=8] blink::IntSize size_
      data +0x28 [sizeof=4] int repetition_count_
      data +0x2c [sizeof=1] bool has_embedded_color_space_
      <padding> (3 bytes)
      data +0x30 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x38 [sizeof=1] bool can_yuv_decode_
      data +0x39 [sizeof=1] bool has_hot_spot_
      <padding> (2 bytes)
      data +0x3c [sizeof=8] blink::IntPoint hot_spot_
      <padding> (4 bytes)
      data +0x48 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x58 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }

After:
    class blink::DeferredImageDecoder [sizeof = 80] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x10 [sizeof=8] WTF::String filename_extension_
      data +0x18 [sizeof=8] blink::IntSize size_
      data +0x20 [sizeof=4] int repetition_count_
      data +0x24 [sizeof=1] bool has_embedded_color_space_
      data +0x25 [sizeof=1] bool all_data_received_
      data +0x26 [sizeof=1] bool can_yuv_decode_
      data +0x27 [sizeof=1] bool has_hot_spot_
      data +0x28 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x30 [sizeof=8] blink::IntPoint hot_spot_
      data +0x38 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x48 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }


BUG=710933
==========

[stanisc, 2017-05-05 21:13:58]

stanisc@chromium.org changed reviewers:
+ chrishtr@chromium.org

[stanisc, 2017-05-05 21:13:59]

PTAL!

[chrishtr, 2017-05-05 22:34:02]

lgtm

[stanisc, 2017-05-06 00:12:32]

The CQ bit was checked by stanisc@chromium.org

[commit-bot: I haz the power, 2017-05-06 00:13:18]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-06 19:24:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-06 19:24:50]

Try jobs failed on following builders:
  chromeos_amd64-generic_chromium_compile_only_ng on
master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_amd64-...)

[stanisc, 2017-05-08 20:49:31]

The CQ bit was checked by stanisc@chromium.org

[commit-bot: I haz the power, 2017-05-08 20:50:09]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-08 20:53:36]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-08 20:53:37]

Try jobs failed on following builders:
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[stanisc, 2017-05-08 23:29:25]

The CQ bit was checked by stanisc@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-08 23:35:51]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[stanisc, 2017-05-09 00:09:00]

Description was changed from

==========
Blink class layout optimization to reduce memory usage

This change optimizes class layout on 64-bit in 4 blink classes, all
related to images. Considering the 16 bit allocation granularity
this saves 16 bytes per instance of each class. It looks like a
typical web page might have up to a few hundred instances of each
class so the total memory saving ~ 16-32 KB per Renderer process,
potentially more for image heavy pages.

Layout details:

Before:
    class blink::Image [sizeof = 40]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8] 
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      <padding> (4 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
      data +0x20 [sizeof=1] bool image_observer_disabled_
      <padding> (7 bytes)
    }

After:
   class blink::Image [sizeof = 32]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8]
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      data +0x0c [sizeof=1] bool image_observer_disabled_
      <padding> (3 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
    }

Before:
    class blink::BitmapImage [sizeof = 280]
      : public blink::Image {
      base +0x00 [sizeof=33] blink::Image
      <padding> (7 bytes)
      data +0x28 [sizeof=112] blink::ImageSource source_
      data +0x98 [sizeof=8] blink::IntSize size_
      data +0xa0 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa8 [sizeof=8] unsigned __int64 current_frame_
      data +0xb0 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd8 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xe0 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe8 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      data +0xf8 [sizeof=4] int repetitions_complete_
      <padding> (4 bytes)
      data +0x100 [sizeof=8] double desired_frame_start_time_
      data +0x108 [sizeof=8] unsigned __int64 frame_count_
      data +0x110 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0x114 [sizeof=1] bool animation_finished_ : 1
      data +0x114 [sizeof=1] bool all_data_received_ : 1
      data +0x114 [sizeof=1] bool have_size_ : 1
      data +0x114 [sizeof=1] bool size_available_ : 1
      data +0x114 [sizeof=1] bool have_frame_count_ : 1
      <padding> (3 bytes)
    }

After:
    class blink::BitmapImage [sizeof = 264]
      : public blink::Image {
      base +0x00 [sizeof=32] blink::Image
      data +0x20 [sizeof=112] blink::ImageSource source_
      data +0x90 [sizeof=8] blink::IntSize size_
      data +0x98 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa0 [sizeof=8] unsigned __int64 current_frame_
      data +0xa8 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd0 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xd8 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe0 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xe8 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0xec [sizeof=1] bool animation_finished_ : 1
      data +0xec [sizeof=1] bool all_data_received_ : 1
      data +0xec [sizeof=1] bool have_size_ : 1
      data +0xec [sizeof=1] bool size_available_ : 1
      data +0xec [sizeof=1] bool have_frame_count_ : 1
      data +0xed [sizeof=1] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      <padding> (2 bytes)
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] int repetitions_complete_
      data +0xf8 [sizeof=8] double desired_frame_start_time_
      data +0x100 [sizeof=8] unsigned __int64 frame_count_
    }

Before:
    class blink::ImageResourceContent [sizeof = 88]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      <padding> (7 bytes)
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x20 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x38 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
      data +0x50 [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x54 [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x55 [sizeof=1] bool is_add_remove_observer_prohibited_
      <padding> (2 bytes)
    }

After:
    class blink::ImageResourceContent [sizeof = 80]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      data +0x09 [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x0a [sizeof=1] bool is_add_remove_observer_prohibited_
      <padding> (1 bytes)
      data +0x0c [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x20 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x38 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
    }

Before:
    class blink::DeferredImageDecoder [sizeof = 96] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=1] bool all_data_received_
      <padding> (7 bytes)
      data +0x10 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x18 [sizeof=8] WTF::String filename_extension_
      data +0x20 [sizeof=8] blink::IntSize size_
      data +0x28 [sizeof=4] int repetition_count_
      data +0x2c [sizeof=1] bool has_embedded_color_space_
      <padding> (3 bytes)
      data +0x30 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x38 [sizeof=1] bool can_yuv_decode_
      data +0x39 [sizeof=1] bool has_hot_spot_
      <padding> (2 bytes)
      data +0x3c [sizeof=8] blink::IntPoint hot_spot_
      <padding> (4 bytes)
      data +0x48 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x58 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }

After:
    class blink::DeferredImageDecoder [sizeof = 80] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x10 [sizeof=8] WTF::String filename_extension_
      data +0x18 [sizeof=8] blink::IntSize size_
      data +0x20 [sizeof=4] int repetition_count_
      data +0x24 [sizeof=1] bool has_embedded_color_space_
      data +0x25 [sizeof=1] bool all_data_received_
      data +0x26 [sizeof=1] bool can_yuv_decode_
      data +0x27 [sizeof=1] bool has_hot_spot_
      data +0x28 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x30 [sizeof=8] blink::IntPoint hot_spot_
      data +0x38 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x48 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }


BUG=710933
==========

to

==========
Blink class layout optimization to reduce memory usage

This change optimizes class layout on 64-bit in 4 blink classes, all
related to images. Considering the 16 bit allocation granularity
this saves 16 bytes per instance of each class. It looks like a
typical web page might have up to a few hundred instances of each
class so the total memory saving ~ 16-32 KB per Renderer process,
potentially more for image heavy pages.

UPDATE: crrev.com/2746343002 added a new field to ImageResourceContent
which further increased it size by 8 bytes. I've moved the fields
around again to still make it squeeze into 80 bytes.

Layout details:

Before:
    class blink::Image [sizeof = 40]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8] 
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      <padding> (4 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
      data +0x20 [sizeof=1] bool image_observer_disabled_
      <padding> (7 bytes)
    }

After:
   class blink::Image [sizeof = 32]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8]
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      data +0x0c [sizeof=1] bool image_observer_disabled_
      <padding> (3 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
    }

Before:
    class blink::BitmapImage [sizeof = 280]
      : public blink::Image {
      base +0x00 [sizeof=33] blink::Image
      <padding> (7 bytes)
      data +0x28 [sizeof=112] blink::ImageSource source_
      data +0x98 [sizeof=8] blink::IntSize size_
      data +0xa0 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa8 [sizeof=8] unsigned __int64 current_frame_
      data +0xb0 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd8 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xe0 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe8 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      data +0xf8 [sizeof=4] int repetitions_complete_
      <padding> (4 bytes)
      data +0x100 [sizeof=8] double desired_frame_start_time_
      data +0x108 [sizeof=8] unsigned __int64 frame_count_
      data +0x110 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0x114 [sizeof=1] bool animation_finished_ : 1
      data +0x114 [sizeof=1] bool all_data_received_ : 1
      data +0x114 [sizeof=1] bool have_size_ : 1
      data +0x114 [sizeof=1] bool size_available_ : 1
      data +0x114 [sizeof=1] bool have_frame_count_ : 1
      <padding> (3 bytes)
    }

After:
    class blink::BitmapImage [sizeof = 264]
      : public blink::Image {
      base +0x00 [sizeof=32] blink::Image
      data +0x20 [sizeof=112] blink::ImageSource source_
      data +0x90 [sizeof=8] blink::IntSize size_
      data +0x98 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa0 [sizeof=8] unsigned __int64 current_frame_
      data +0xa8 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd0 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xd8 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe0 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xe8 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0xec [sizeof=1] bool animation_finished_ : 1
      data +0xec [sizeof=1] bool all_data_received_ : 1
      data +0xec [sizeof=1] bool have_size_ : 1
      data +0xec [sizeof=1] bool size_available_ : 1
      data +0xec [sizeof=1] bool have_frame_count_ : 1
      data +0xed [sizeof=1] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      <padding> (2 bytes)
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] int repetitions_complete_
      data +0xf8 [sizeof=8] double desired_frame_start_time_
      data +0x100 [sizeof=8] unsigned __int64 frame_count_
    }

Before:
    class blink::ImageResourceContent [sizeof = 96]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      <padding> (7 bytes)
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=4] blink::ResourceStatus content_status_
      <padding> (4 bytes)
      data +0x20 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x28 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x40 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
      data +0x58 [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x5C [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x5D [sizeof=1] bool is_add_remove_observer_prohibited_
      <padding> (2 bytes)
    }

After:
    class blink::ImageResourceContent [sizeof = 80]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      data +0x09 [sizeof=1] blink::ResourceStatus content_status_
      data +0x0a [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x0b [sizeof=1] bool is_add_remove_observer_prohibited_
      data +0x0c [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x20 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x38 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
    }

Before:
    class blink::DeferredImageDecoder [sizeof = 96] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=1] bool all_data_received_
      <padding> (7 bytes)
      data +0x10 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x18 [sizeof=8] WTF::String filename_extension_
      data +0x20 [sizeof=8] blink::IntSize size_
      data +0x28 [sizeof=4] int repetition_count_
      data +0x2c [sizeof=1] bool has_embedded_color_space_
      <padding> (3 bytes)
      data +0x30 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x38 [sizeof=1] bool can_yuv_decode_
      data +0x39 [sizeof=1] bool has_hot_spot_
      <padding> (2 bytes)
      data +0x3c [sizeof=8] blink::IntPoint hot_spot_
      <padding> (4 bytes)
      data +0x48 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x58 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }

After:
    class blink::DeferredImageDecoder [sizeof = 80] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x10 [sizeof=8] WTF::String filename_extension_
      data +0x18 [sizeof=8] blink::IntSize size_
      data +0x20 [sizeof=4] int repetition_count_
      data +0x24 [sizeof=1] bool has_embedded_color_space_
      data +0x25 [sizeof=1] bool all_data_received_
      data +0x26 [sizeof=1] bool can_yuv_decode_
      data +0x27 [sizeof=1] bool has_hot_spot_
      data +0x28 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x30 [sizeof=8] blink::IntPoint hot_spot_
      data +0x38 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x48 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }


BUG=710933
==========

[stanisc, 2017-05-09 00:15:29]

stanisc@chromium.org changed reviewers:
+ yhirano@chromium.org

[stanisc, 2017-05-09 00:15:29]

+ yhirano@chromium.org for
third_party/WebKit/Source/platform/loader/fetch/ResourceStatus.h

[commit-bot: I haz the power, 2017-05-09 00:23:35]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-09 00:23:35]

Dry run: Try jobs failed on following builders:
  win_chromium_compile_dbg_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_comp...)
  win_chromium_x64_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)
  win_clang on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_clang/builds/...)

[yhirano, 2017-05-09 04:17:56]

On 2017/05/09 00:15:29, stanisc wrote:
> + mailto:yhirano@chromium.org for
> third_party/WebKit/Source/platform/loader/fetch/ResourceStatus.h

platform/loader lgtm

[stanisc, 2017-05-09 17:29:08]

The CQ bit was checked by stanisc@chromium.org

[stanisc, 2017-05-09 17:29:08]

The patchset sent to the CQ was uploaded after l-g-t-m from
chrishtr@chromium.org
Link to the patchset: https://codereview.chromium.org/2859313003/#ps40001
(title: "Resolved merge conflict and changed blink::ResourceStatus enum to be
based on uint8_t")

[commit-bot: I haz the power, 2017-05-09 17:29:57]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-09 17:47:59]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1494350948173470,
"parent_rev": "c6a32ecf073cb1616e51c927b2bfdad46a539c31", "commit_rev":
"4f54bee9b89dd593c338dbc684f806bb73b48256"}

[commit-bot: I haz the power, 2017-05-09 17:48:32]

Description was changed from

==========
Blink class layout optimization to reduce memory usage

This change optimizes class layout on 64-bit in 4 blink classes, all
related to images. Considering the 16 bit allocation granularity
this saves 16 bytes per instance of each class. It looks like a
typical web page might have up to a few hundred instances of each
class so the total memory saving ~ 16-32 KB per Renderer process,
potentially more for image heavy pages.

UPDATE: crrev.com/2746343002 added a new field to ImageResourceContent
which further increased it size by 8 bytes. I've moved the fields
around again to still make it squeeze into 80 bytes.

Layout details:

Before:
    class blink::Image [sizeof = 40]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8] 
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      <padding> (4 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
      data +0x20 [sizeof=1] bool image_observer_disabled_
      <padding> (7 bytes)
    }

After:
   class blink::Image [sizeof = 32]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8]
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      data +0x0c [sizeof=1] bool image_observer_disabled_
      <padding> (3 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
    }

Before:
    class blink::BitmapImage [sizeof = 280]
      : public blink::Image {
      base +0x00 [sizeof=33] blink::Image
      <padding> (7 bytes)
      data +0x28 [sizeof=112] blink::ImageSource source_
      data +0x98 [sizeof=8] blink::IntSize size_
      data +0xa0 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa8 [sizeof=8] unsigned __int64 current_frame_
      data +0xb0 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd8 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xe0 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe8 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      data +0xf8 [sizeof=4] int repetitions_complete_
      <padding> (4 bytes)
      data +0x100 [sizeof=8] double desired_frame_start_time_
      data +0x108 [sizeof=8] unsigned __int64 frame_count_
      data +0x110 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0x114 [sizeof=1] bool animation_finished_ : 1
      data +0x114 [sizeof=1] bool all_data_received_ : 1
      data +0x114 [sizeof=1] bool have_size_ : 1
      data +0x114 [sizeof=1] bool size_available_ : 1
      data +0x114 [sizeof=1] bool have_frame_count_ : 1
      <padding> (3 bytes)
    }

After:
    class blink::BitmapImage [sizeof = 264]
      : public blink::Image {
      base +0x00 [sizeof=32] blink::Image
      data +0x20 [sizeof=112] blink::ImageSource source_
      data +0x90 [sizeof=8] blink::IntSize size_
      data +0x98 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa0 [sizeof=8] unsigned __int64 current_frame_
      data +0xa8 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd0 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xd8 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe0 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xe8 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0xec [sizeof=1] bool animation_finished_ : 1
      data +0xec [sizeof=1] bool all_data_received_ : 1
      data +0xec [sizeof=1] bool have_size_ : 1
      data +0xec [sizeof=1] bool size_available_ : 1
      data +0xec [sizeof=1] bool have_frame_count_ : 1
      data +0xed [sizeof=1] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      <padding> (2 bytes)
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] int repetitions_complete_
      data +0xf8 [sizeof=8] double desired_frame_start_time_
      data +0x100 [sizeof=8] unsigned __int64 frame_count_
    }

Before:
    class blink::ImageResourceContent [sizeof = 96]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      <padding> (7 bytes)
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=4] blink::ResourceStatus content_status_
      <padding> (4 bytes)
      data +0x20 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x28 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x40 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
      data +0x58 [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x5C [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x5D [sizeof=1] bool is_add_remove_observer_prohibited_
      <padding> (2 bytes)
    }

After:
    class blink::ImageResourceContent [sizeof = 80]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      data +0x09 [sizeof=1] blink::ResourceStatus content_status_
      data +0x0a [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x0b [sizeof=1] bool is_add_remove_observer_prohibited_
      data +0x0c [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x20 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x38 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
    }

Before:
    class blink::DeferredImageDecoder [sizeof = 96] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=1] bool all_data_received_
      <padding> (7 bytes)
      data +0x10 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x18 [sizeof=8] WTF::String filename_extension_
      data +0x20 [sizeof=8] blink::IntSize size_
      data +0x28 [sizeof=4] int repetition_count_
      data +0x2c [sizeof=1] bool has_embedded_color_space_
      <padding> (3 bytes)
      data +0x30 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x38 [sizeof=1] bool can_yuv_decode_
      data +0x39 [sizeof=1] bool has_hot_spot_
      <padding> (2 bytes)
      data +0x3c [sizeof=8] blink::IntPoint hot_spot_
      <padding> (4 bytes)
      data +0x48 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x58 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }

After:
    class blink::DeferredImageDecoder [sizeof = 80] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x10 [sizeof=8] WTF::String filename_extension_
      data +0x18 [sizeof=8] blink::IntSize size_
      data +0x20 [sizeof=4] int repetition_count_
      data +0x24 [sizeof=1] bool has_embedded_color_space_
      data +0x25 [sizeof=1] bool all_data_received_
      data +0x26 [sizeof=1] bool can_yuv_decode_
      data +0x27 [sizeof=1] bool has_hot_spot_
      data +0x28 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x30 [sizeof=8] blink::IntPoint hot_spot_
      data +0x38 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x48 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }


BUG=710933
==========

to

==========
Blink class layout optimization to reduce memory usage

This change optimizes class layout on 64-bit in 4 blink classes, all
related to images. Considering the 16 bit allocation granularity
this saves 16 bytes per instance of each class. It looks like a
typical web page might have up to a few hundred instances of each
class so the total memory saving ~ 16-32 KB per Renderer process,
potentially more for image heavy pages.

UPDATE: crrev.com/2746343002 added a new field to ImageResourceContent
which further increased it size by 8 bytes. I've moved the fields
around again to still make it squeeze into 80 bytes.

Layout details:

Before:
    class blink::Image [sizeof = 40]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8] 
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      <padding> (4 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
      data +0x20 [sizeof=1] bool image_observer_disabled_
      <padding> (7 bytes)
    }

After:
   class blink::Image [sizeof = 32]
      : public WTF::ThreadSafeRefCounted<blink::Image> {
      vfptr +0x00 [sizeof=8]
      base +0x08 [sizeof=4] WTF::ThreadSafeRefCounted<blink::Image>
      data +0x0c [sizeof=1] bool image_observer_disabled_
      <padding> (3 bytes)
      data +0x10 [sizeof=8] WTF::RefPtr<blink::SharedBuffer> encoded_image_data_
      data +0x18 [sizeof=8] blink::UntracedMember<blink::ImageObserver>
image_observer_
    }

Before:
    class blink::BitmapImage [sizeof = 280]
      : public blink::Image {
      base +0x00 [sizeof=33] blink::Image
      <padding> (7 bytes)
      data +0x28 [sizeof=112] blink::ImageSource source_
      data +0x98 [sizeof=8] blink::IntSize size_
      data +0xa0 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa8 [sizeof=8] unsigned __int64 current_frame_
      data +0xb0 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd8 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xe0 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe8 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      data +0xf8 [sizeof=4] int repetitions_complete_
      <padding> (4 bytes)
      data +0x100 [sizeof=8] double desired_frame_start_time_
      data +0x108 [sizeof=8] unsigned __int64 frame_count_
      data +0x110 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0x114 [sizeof=1] bool animation_finished_ : 1
      data +0x114 [sizeof=1] bool all_data_received_ : 1
      data +0x114 [sizeof=1] bool have_size_ : 1
      data +0x114 [sizeof=1] bool size_available_ : 1
      data +0x114 [sizeof=1] bool have_frame_count_ : 1
      <padding> (3 bytes)
    }

After:
    class blink::BitmapImage [sizeof = 264]
      : public blink::Image {
      base +0x00 [sizeof=32] blink::Image
      data +0x20 [sizeof=112] blink::ImageSource source_
      data +0x90 [sizeof=8] blink::IntSize size_
      data +0x98 [sizeof=8] blink::IntSize size_respecting_orientation_
      data +0xa0 [sizeof=8] unsigned __int64 current_frame_
      data +0xa8 [sizeof=40]
WTF::Vector<blink::FrameData,1,WTF::PartitionAllocator> frames_
      data +0xd0 [sizeof=8] sk_sp<SkImage> cached_frame_
      data +0xd8 [sizeof=8] unsigned __int64 cached_frame_index_
      data +0xe0 [sizeof=8] std::unique_ptr<...> frame_timer_
      data +0xe8 [sizeof=4] blink::ImageAnimationPolicy animation_policy_
      data +0xec [sizeof=1] bool animation_finished_ : 1
      data +0xec [sizeof=1] bool all_data_received_ : 1
      data +0xec [sizeof=1] bool have_size_ : 1
      data +0xec [sizeof=1] bool size_available_ : 1
      data +0xec [sizeof=1] bool have_frame_count_ : 1
      data +0xed [sizeof=1] blink::BitmapImage::RepetitionCountStatus
repetition_count_status_
      <padding> (2 bytes)
      data +0xf0 [sizeof=4] int repetition_count_
      data +0xf4 [sizeof=4] int repetitions_complete_
      data +0xf8 [sizeof=8] double desired_frame_start_time_
      data +0x100 [sizeof=8] unsigned __int64 frame_count_
    }

Before:
    class blink::ImageResourceContent [sizeof = 96]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      <padding> (7 bytes)
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=4] blink::ResourceStatus content_status_
      <padding> (4 bytes)
      data +0x20 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x28 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x40 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
      data +0x58 [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x5C [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x5D [sizeof=1] bool is_add_remove_observer_prohibited_
      <padding> (2 bytes)
    }

After:
    class blink::ImageResourceContent [sizeof = 80]
      : public blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      , public blink::ImageObserver {
      base +0x00 [sizeof=8] blink::ImageObserver
      base +0x08 [sizeof=1]
blink::GarbageCollectedFinalized<blink::ImageResourceContent>
      data +0x09 [sizeof=1] blink::ResourceStatus content_status_
      data +0x0a [sizeof=1] bool is_refetchable_data_from_disk_cache_
      data +0x0b [sizeof=1] bool is_add_remove_observer_prohibited_
      data +0x0c [sizeof=4] blink::Image::SizeAvailability size_available_
      data +0x10 [sizeof=8] blink::Member<blink::ImageResourceInfo> info_
      data +0x18 [sizeof=8] WTF::RefPtr<blink::Image> image_
      data +0x20 [sizeof=24] WTF::HashCountedSet<...> observers_
      data +0x38 [sizeof=24] WTF::HashCountedSet<...> finished_observers_
    }

Before:
    class blink::DeferredImageDecoder [sizeof = 96] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=1] bool all_data_received_
      <padding> (7 bytes)
      data +0x10 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x18 [sizeof=8] WTF::String filename_extension_
      data +0x20 [sizeof=8] blink::IntSize size_
      data +0x28 [sizeof=4] int repetition_count_
      data +0x2c [sizeof=1] bool has_embedded_color_space_
      <padding> (3 bytes)
      data +0x30 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x38 [sizeof=1] bool can_yuv_decode_
      data +0x39 [sizeof=1] bool has_hot_spot_
      <padding> (2 bytes)
      data +0x3c [sizeof=8] blink::IntPoint hot_spot_
      <padding> (4 bytes)
      data +0x48 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x58 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }

After:
    class blink::DeferredImageDecoder [sizeof = 80] {
      data +0x00 [sizeof=8] std::unique_ptr<...> rw_buffer_
      data +0x08 [sizeof=8] std::unique_ptr<...> actual_decoder_
      data +0x10 [sizeof=8] WTF::String filename_extension_
      data +0x18 [sizeof=8] blink::IntSize size_
      data +0x20 [sizeof=4] int repetition_count_
      data +0x24 [sizeof=1] bool has_embedded_color_space_
      data +0x25 [sizeof=1] bool all_data_received_
      data +0x26 [sizeof=1] bool can_yuv_decode_
      data +0x27 [sizeof=1] bool has_hot_spot_
      data +0x28 [sizeof=8] sk_sp<SkColorSpace> color_space_for_sk_images_
      data +0x30 [sizeof=8] blink::IntPoint hot_spot_
      data +0x38 [sizeof=16] WTF::Vector<...> frame_data_
      data +0x48 [sizeof=8] WTF::RefPtr<...> frame_generator_
    }


BUG=710933

Review-Url: https://codereview.chromium.org/2859313003
Cr-Commit-Position: refs/heads/master@{#470373}
Committed:
https://chromium.googlesource.com/chromium/src/+/4f54bee9b89dd593c338dbc684f8...
==========

[commit-bot: I haz the power, 2017-05-09 17:48:36]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/chromium/src/+/4f54bee9b89dd593c338dbc684f8...