Also convert CodeView to a class and fix a host of selection
bugs in the process, as well as move the logic and data to
"enrich" location with one type of location data with location
data known globally to the whole graph in the selection broker.

Review-Url: https://codereview.chromium.org/2230083004
Cr-Commit-Position: refs/heads/master@{#38544}

perf-turbo.py merges a perf data file and a turbofan trace file into a
single json object which can then be piped to a file and uploaded to
turbolizer to display the profiling data in the disassembly. With the
changes, turbolizer now shows the event counts for instruction in
percentage form and with heatmap-stype colouring. Multiple different
events can be recorded at once with a new drop-down menu to select which
event to view the counts of. The documentation has been updated with
instructions. Using the script is optional and turbolizer retains
previous functionality if a trace without profiling data is uploaded.

BUG=None

Review-Url: https://codereview.chromium.org/2174803002
Cr-Commit-Position: refs/heads/master@{#38124}

Review-Url: https://codereview.chromium.org/729913004
Cr-Commit-Position: refs/heads/master@{#36351}