Auto merge of #20132 - nakul02:issue_19223, r=jdm

Profiler for blocked IpcReceiver::recv()

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Implements feature #19223

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #19223 (github issue number if applicable).

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- [x] There are tests for these changes

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WIP.
@jdm - this is the new profiler : "Blocked at IPC Receive"
Should I dig through all the calls to `ipc::channel` and replace them with this profiled `IpcReceiver`?

![screenshot from 2018-02-27 01-35-37](https://user-images.githubusercontent.com/5394361/36721061-b46edea4-1b5e-11e8-91d6-7faba742f237.png)

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Cargo.lock

@@ -2258,12 +2258,14 @@ dependencies = [
  "profile 0.0.1",
  "profile_traits 0.0.1",
  "servo_allocator 0.0.1",
+ "servo_config 0.0.1",
 ]
 
 [[package]]
 name = "profile_traits"
 version = "0.0.1"
 dependencies = [
+ "bincode 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "energy-monitor 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "energymon 0.3.0 (git+https://github.com/energymon/energymon-rust.git)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",