Free memory when the last WebView instance is destroyed.

Free memory when the last WebView instance is destroyed.

Sending a (TRIM_MEMORY_COMPLETE) memory pressure signal to free some
memory (v8,sqlite,image decoding caches) when the last WebView instance
is destroyed.

BUG=284362
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=221669

[joth, 2013-09-03 18:37:58]

https://codereview.chromium.org/23888003/diff/7001/android_webview/java/src/o...
File android_webview/java/src/org/chromium/android_webview/AwContents.java
(right):

https://codereview.chromium.org/23888003/diff/7001/android_webview/java/src/o...
android_webview/java/src/org/chromium/android_webview/AwContents.java:204:
ComponentCallbacks2.TRIM_MEMORY_COMPLETE);
It's always a bit hairy adding new code to the CleanupReference as it's very
easy to introduce memory leak.
This change looks safe. But just to check could we do this in the native d'tor
by calling  base::MemoryPressureListener::NotifyMemoryPressure() instead?

[Primiano Tucci (use gerrit), 2013-09-05 11:47:25]

https://codereview.chromium.org/23888003/diff/7001/android_webview/java/src/o...
File android_webview/java/src/org/chromium/android_webview/AwContents.java
(right):

https://codereview.chromium.org/23888003/diff/7001/android_webview/java/src/o...
android_webview/java/src/org/chromium/android_webview/AwContents.java:204:
ComponentCallbacks2.TRIM_MEMORY_COMPLETE);
On 2013/09/03 18:37:58, joth wrote:
> It's always a bit hairy adding new code to the CleanupReference as it's very
> easy to introduce memory leak.
> This change looks safe. But just to check could we do this in the native d'tor
> by calling  base::MemoryPressureListener::NotifyMemoryPressure() instead?

Done.

[joth, 2013-09-05 16:27:33]

lgtm

[joth, 2013-09-05 16:29:30]

maybe add a comment
"When the final WebView is destroyed free all discardable chromium allocated
memory, because the app process may continue to run for a long time without ever
using another WebView.

[commit-bot: I haz the power, 2013-09-06 09:56:31]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/primiano@chromium.org/23888003/20001

[commit-bot: I haz the power, 2013-09-06 10:12:44]

Change committed as 221669