Rename lots of things from 'sRGB' to 'GammaCorrect', where appropriate

Trying to be much more explicit about where we really mean sRGB as a format,
and where we mean gamma-correct, as in: "not legacy behavior". Most of the
changes to rendering behavior are dependent on the latter, so let's be precise.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1884873006

Review URL: https://codereview.chromium.org/1884873006
diff --git a/src/gpu/text/GrAtlasTextBlob.cpp b/src/gpu/text/GrAtlasTextBlob.cpp
index 60f905d..65b84dd 100644
--- a/src/gpu/text/GrAtlasTextBlob.cpp
+++ b/src/gpu/text/GrAtlasTextBlob.cpp
@@ -257,7 +257,7 @@
                                               GrColor color,
                                               const SkPaint& skPaint, const SkSurfaceProps& props,
                                               const GrDistanceFieldAdjustTable* distanceAdjustTable,
-                                              bool useSRGBDistanceTable,
+                                              bool useGammaCorrectDistanceTable,
                                               GrBatchFontCache* cache) {
     GrMaskFormat format = info.maskFormat();
     GrColor subRunColor;
@@ -279,7 +279,8 @@
         }
         bool useBGR = SkPixelGeometryIsBGR(props.pixelGeometry());
         batch = GrAtlasTextBatch::CreateDistanceField(glyphCount, cache,
-                                                      distanceAdjustTable, useSRGBDistanceTable,
+                                                      distanceAdjustTable,
+                                                      useGammaCorrectDistanceTable,
                                                       filteredColor, info.hasUseLCDText(), useBGR);
     } else {
         batch = GrAtlasTextBatch::CreateBitmap(format, glyphCount, cache);
@@ -311,13 +312,13 @@
             continue;
         }
 
-        bool useSRGBDistanceTable = GrPixelConfigIsSRGB(dc->accessRenderTarget()->config()) &&
+        bool useGammaCorrectTable = GrPixelConfigIsSRGB(dc->accessRenderTarget()->config()) &&
                                     !pipelineBuilder->getDisableOutputConversionToSRGB();
 
         SkAutoTUnref<GrDrawBatch> batch(this->createBatch(info, glyphCount, run,
                                                           subRun, viewMatrix, x, y, color,
                                                           skPaint, props,
-                                                          distanceAdjustTable, useSRGBDistanceTable,
+                                                          distanceAdjustTable, useGammaCorrectTable,
                                                           cache));
         dc->drawBatch(pipelineBuilder, batch);
     }