[DevTools] Check request_id in DevToolsUIBindings::IndexPath

[DevTools] Check request_id in DevToolsUIBindings::IndexPath

If request_id is reused before the previous job with the same id is finished the old job won't be stopped in ~DevToolsUIBindings.

BUG=

Committed: https://crrev.com/88ac3ce8fa6463e5f04d4b3e7e2327e2ec1b3a19
Cr-Commit-Position: refs/heads/master@{#317799}

[vkuzkokov, 2015-02-24 14:26:18]

vkuzkokov@chromium.org changed reviewers:
+ dgozman@chromium.org

[dgozman, 2015-02-24 14:32:31]

lgtm

[vkuzkokov, 2015-02-24 14:33:13]

The CQ bit was checked by vkuzkokov@chromium.org

[commit-bot: I haz the power, 2015-02-24 14:33:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/951953002/1

[commit-bot: I haz the power, 2015-02-24 15:22:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-24 15:23:19]

Patchset 1 (id:??) landed as
https://crrev.com/88ac3ce8fa6463e5f04d4b3e7e2327e2ec1b3a19
Cr-Commit-Position: refs/heads/master@{#317799}

[phoglund_chromium, 2015-02-25 10:19:36]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/956873002/ by phoglund@chromium.org.

The reason for reverting is: Speculative revert:
http://build.chromium.org/p/chromium.mac/builders/Mac10.6%20Tests/builds/4683...
became very flaky on Mac OS X 10.6 about when this patch was introduced. This is
the only devtools change near to the start of the flakiness.

The errors are:
DevToolsSanityTest.TestReattachAfterCrash (run #1):
[ RUN      ] DevToolsSanityTest.TestReattachAfterCrash
[32422:28675:0224/105826:WARNING:data_reduction_proxy_config.cc(211)] SPDY proxy
OFF at startup
HTTP server started on http://127.0.0.1:64960...
sending server_data: {"host": "127.0.0.1", "port": 64960} (36 bytes)
[32427:9479:0224/105828:WARNING:channel.cc(547)] Failed to send message to ack
remove remote endpoint (local ID 1, remote ID 1)
[32427:9479:0224/105828:WARNING:channel.cc(547)] Failed to send message to ack
remove remote endpoint (local ID 2147483648, remote ID 2.