Reland "Ensure |m_image| is (re-)created in ImageResource::didAddClient()"

Reland "Ensure |m_image| is (re-)created in ImageResource::didAddClient()"

After ImageResource is pruned, |m_image| can be turned into null, but is not
re-created when ResourceClient is added to ImageResource later.
We re-create |m_image| when ImageResourceObserver is added in
ImageResource::addObserver().
This CL do the same thing in ImageResource::didAddClient() to ensure |m_image|
is non-null when ImageResource is reused after pruning.

This is regression since ImageResourceClient was split into ResourceClient and
ImageResourceObserver but the |m_image| re-creation logic was put only in the
ImageResourceObserver path and not in the ResourceClient path:
  https://codereview.chromium.org/1706083002
  https://codereview.chromium.org/1728313003

BUG=618597, 587663
TBR=mkwst@chromium.org, yhirano@chromium.org, hajimehoshi@chromium.org

Review-Url: https://codereview.chromium.org/2141843003
Cr-Commit-Position: refs/heads/master@{#405024}
(cherry picked from commit d415aad374ad81906840afbf4c05f0594f1f581b)

Committed: https://chromium.googlesource.com/chromium/src/+/79706ed327e0b6bb0ac98e7ae50c837fe049cce7

[hiroshige, 2016-07-22 08:40:37]

Description was changed from

==========
Reland "Ensure |m_image| is (re-)created in ImageResource::didAddClient()"

After ImageResource is pruned, |m_image| can be turned into null, but is not
re-created when ResourceClient is added to ImageResource later.
We re-create |m_image| when ImageResourceObserver is added in
ImageResource::addObserver().
This CL do the same thing in ImageResource::didAddClient() to ensure |m_image|
is non-null when ImageResource is reused after pruning.

This is regression since ImageResourceClient was split into ResourceClient and
ImageResourceObserver but the |m_image| re-creation logic was put only in the
ImageResourceObserver path and not in the ResourceClient path:
  https://codereview.chromium.org/1706083002
  https://codereview.chromium.org/1728313003

BUG=618597, 587663
TBR=mkwst@chromium.org, yhirano@chromium.org, hajimehoshi@chromium.org

Review-Url: https://codereview.chromium.org/2141843003
Cr-Commit-Position: refs/heads/master@{#405024}
(cherry picked from commit d415aad374ad81906840afbf4c05f0594f1f581b)
==========

to

==========
Reland "Ensure |m_image| is (re-)created in ImageResource::didAddClient()"

After ImageResource is pruned, |m_image| can be turned into null, but is not
re-created when ResourceClient is added to ImageResource later.
We re-create |m_image| when ImageResourceObserver is added in
ImageResource::addObserver().
This CL do the same thing in ImageResource::didAddClient() to ensure |m_image|
is non-null when ImageResource is reused after pruning.

This is regression since ImageResourceClient was split into ResourceClient and
ImageResourceObserver but the |m_image| re-creation logic was put only in the
ImageResourceObserver path and not in the ResourceClient path:
  https://codereview.chromium.org/1706083002
  https://codereview.chromium.org/1728313003

BUG=618597, 587663
TBR=mkwst@chromium.org, yhirano@chromium.org, hajimehoshi@chromium.org

Review-Url: https://codereview.chromium.org/2141843003
Cr-Commit-Position: refs/heads/master@{#405024}
(cherry picked from commit d415aad374ad81906840afbf4c05f0594f1f581b)

Committed:
https://chromium.googlesource.com/chromium/src/+/79706ed327e0b6bb0ac98e7ae50c...
==========

[hiroshige, 2016-07-22 08:40:41]

Committed patchset #1 (id:1) manually as
79706ed327e0b6bb0ac98e7ae50c837fe049cce7 (presubmit successful).