Revert of Adding a router class to handle messages that expect responses.

Revert of Adding a router class to handle messages that expect responses. (https://codereview.chromium.org/371603003/)

Reason for revert:
This appears to have broken mojotest_instrumentation_tests with the errors like the ones listed below.

http://build.chromium.org/p/chromium.webkit/builders/Android%20Tests%20%28dbg%29/builds/20270

C   52.086s Main  [FAIL] org.chromium.mojo.bindings.ConnectorTest#testErrors:
C   52.086s Main  java.lang.NoClassDefFoundError: java.util.Objects
C   52.086s Main  	at org.chromium.mojo.bindings.MessageHeader.equals(MessageHeader.java:189)
C   52.086s Main  	at org.chromium.mojo.bindings.MessageWithHeader.<init>(MessageWithHeader.java:29)
C   52.086s Main  	at org.chromium.mojo.bindings.MessageWithHeader.<init>(MessageWithHeader.java:39)
C   52.086s Main  	at org.chromium.mojo.bindings.BindingsTestUtils.newRandomMessageWithHeader(BindingsTestUtils.java:85)
C   52.086s Main  	at org.chromium.mojo.bindings.ConnectorTest.setUp(ConnectorTest.java:53)
C   52.086s Main  	at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:191)
C   52.086s Main  	at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:176)
C   52.086s Main  	at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:554)
C   52.086s Main  	at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1701)

C   52.091s Main  [CRASH] org.chromium.mojo.bindings.RouterTest#testReceivingViaRouterWithResponse:
C   52.091s Main  Native crash: Segmentation fault

Original issue's description:
> Adding a router class to handle messages that expect responses.
> 
> This also introduce the notion of message header to allow routing.
> 
> R=rmcilroy@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283767

TBR=qsr
NOTREECHECKS=true
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284059

[johnme, 2014-07-18 11:18:33]

Created Revert of Adding a router class to handle messages that expect
responses.

[commit-bot: I haz the power, 2014-07-18 11:19:58]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/johnme@chromium.org/392223004/1

[Peter Beverloo, 2014-07-18 11:19:59]

Best to only list one failure instead of all, it adds a lot of noise for close
to zero gain.

[commit-bot: I haz the power, 2014-07-18 11:19:59]

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

[commit-bot: I haz the power, 2014-07-18 11:20:00]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[johnme, 2014-07-18 11:21:19]

The CQ bit was unchecked by johnme@chromium.org

[johnme, 2014-07-18 11:22:55]

The CQ bit was checked by johnme@chromium.org

[commit-bot: I haz the power, 2014-07-18 11:24:00]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/johnme@chromium.org/392223004/1

[commit-bot: I haz the power, 2014-07-18 11:25:20]

Change committed as 284059

[qsr, 2014-07-18 11:32:44]

lgtm