FlameChart: speed up bars drawing procedure.

FlameChart: speed up bars drawing procedure.

It used to switch fillStyle for every bar. (N times)
With new implementation it will switch fillStyle K times
where K is the number of functions by drawing all the bars for one color in a sequence.

BUG=none
R=yurys@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=157451

[yurys, 2013-09-05 11:43:25]

lgtm

https://codereview.chromium.org/23533037/diff/3001/Source/devtools/front_end/...
File Source/devtools/front_end/FlameChart.js (right):

https://codereview.chromium.org/23533037/diff/3001/Source/devtools/front_end/...
Source/devtools/front_end/FlameChart.js:319: var colorIndexEntryChains = [];
Should we specify the size as the total number of colors? I suspect that the
array may get into the slow mode otherwise.

https://codereview.chromium.org/23533037/diff/3001/Source/devtools/front_end/...
Source/devtools/front_end/FlameChart.js:653: for (var j = 1; j <
colorIndexEntryChains.length; ++j) {
Starting from 1 is unusual, can you change
WebInspector.FlameChart.ColorGenerator to start assigning indexes from 0
instead?

[loislo, 2013-09-06 08:15:56]

https://codereview.chromium.org/23533037/diff/3001/Source/devtools/front_end/...
File Source/devtools/front_end/FlameChart.js (right):

https://codereview.chromium.org/23533037/diff/3001/Source/devtools/front_end/...
Source/devtools/front_end/FlameChart.js:319: var colorIndexEntryChains = [];
On 2013/09/05 11:43:25, Yury Semikhatsky wrote:
> Should we specify the size as the total number of colors? I suspect that the
> array may get into the slow mode otherwise.

Unfortunately we don't know the number of colors before processing.
So, we need to do a separate pass for that.

https://codereview.chromium.org/23533037/diff/3001/Source/devtools/front_end/...
Source/devtools/front_end/FlameChart.js:653: for (var j = 1; j <
colorIndexEntryChains.length; ++j) {
On 2013/09/05 11:43:25, Yury Semikhatsky wrote:
> Starting from 1 is unusual, can you change
> WebInspector.FlameChart.ColorGenerator to start assigning indexes from 0
> instead?

Done.

[loislo, 2013-09-09 11:53:30]

Committed patchset #2 manually as r157451 (presubmit successful).