Rewrite the while loop in DrawingBuffer::createOrRecycleBitmap

Rewrite the while loop in DrawingBuffer::createOrRecycleBitmap

Right now inside while loop we call Vector::remove() and that requires
resizing and copying which is quite expensive. This CL rewrite that
for loop by creating a new local Vector, and copy into it all the elements
that are not supposed to be removed. Then we swap this local Vector
with m_recycledBitmaps.

Committed: https://crrev.com/303824133c0cfff4028742fefe453df5bd222ec5
Cr-Commit-Position: refs/heads/master@{#421884}

[xidachen, 2016-09-29 13:16:26]

Description was changed from

==========
Rewrite the while loop in DrawingBuffer::createOrRecycleBitmap

Right now the while loop in this method
==========

to

==========
Rewrite the while loop in DrawingBuffer::createOrRecycleBitmap

Right now inside while loop we call Vector::remove() and that requires
resizing and copying which is quite expensive. This CL rewrite that
for loop by creating a new local Vector, and copy into it all the elements
that are not supposed to be removed. Then we swap this local Vector
with m_recycledBitmaps.
==========

[xidachen, 2016-09-29 13:16:27]

xidachen@chromium.org changed reviewers:
+ danakj@chromium.org, esprehn@chromium.org, kbr@chromium.org

[jbroman, 2016-09-29 14:02:57]

I don't mean to bikeshed this, but you can save the buffer allocation (without
the quadratic behaviour of calling remove()) by using std::remove_if.

auto it = std::remove_if(m_recycledBitmaps.begin(), m_recycledBitmaps.end(),
    [this](const RecycledBitmap& bitmap) { return bitmap.size != m_size; });
m_recycledBitmaps.shrink(it - m_recycledBitmaps.begin());

[xidachen, 2016-09-29 15:08:49]

Now using std::remove_if which is a O(n) operation, PTAL.

[esprehn, 2016-09-29 16:52:26]

lgtm, very futuristic. :)

[xidachen, 2016-09-29 16:59:18]

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

[commit-bot: I haz the power, 2016-09-29 16:59:47]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[danakj, 2016-09-29 18:28:15]

LGTM

[commit-bot: I haz the power, 2016-09-29 18:35:55]

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

[commit-bot: I haz the power, 2016-09-29 18:35:56]

Dry run: This issue passed the CQ dry run.

[xidachen, 2016-09-29 18:37:44]

The CQ bit was checked by xidachen@chromium.org

[commit-bot: I haz the power, 2016-09-29 18:38:24]

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, 2016-09-29 18:45:40]

Description was changed from

==========
Rewrite the while loop in DrawingBuffer::createOrRecycleBitmap

Right now inside while loop we call Vector::remove() and that requires
resizing and copying which is quite expensive. This CL rewrite that
for loop by creating a new local Vector, and copy into it all the elements
that are not supposed to be removed. Then we swap this local Vector
with m_recycledBitmaps.
==========

to

==========
Rewrite the while loop in DrawingBuffer::createOrRecycleBitmap

Right now inside while loop we call Vector::remove() and that requires
resizing and copying which is quite expensive. This CL rewrite that
for loop by creating a new local Vector, and copy into it all the elements
that are not supposed to be removed. Then we swap this local Vector
with m_recycledBitmaps.
==========

[commit-bot: I haz the power, 2016-09-29 18:45:42]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-09-29 18:48:11]

Description was changed from

==========
Rewrite the while loop in DrawingBuffer::createOrRecycleBitmap

Right now inside while loop we call Vector::remove() and that requires
resizing and copying which is quite expensive. This CL rewrite that
for loop by creating a new local Vector, and copy into it all the elements
that are not supposed to be removed. Then we swap this local Vector
with m_recycledBitmaps.
==========

to

==========
Rewrite the while loop in DrawingBuffer::createOrRecycleBitmap

Right now inside while loop we call Vector::remove() and that requires
resizing and copying which is quite expensive. This CL rewrite that
for loop by creating a new local Vector, and copy into it all the elements
that are not supposed to be removed. Then we swap this local Vector
with m_recycledBitmaps.

Committed: https://crrev.com/303824133c0cfff4028742fefe453df5bd222ec5
Cr-Commit-Position: refs/heads/master@{#421884}
==========

[commit-bot: I haz the power, 2016-09-29 18:48:12]

Patchset 3 (id:??) landed as
https://crrev.com/303824133c0cfff4028742fefe453df5bd222ec5
Cr-Commit-Position: refs/heads/master@{#421884}