Fix a performance regression.
Fix a performance regression.

"Refactor BufferStorage11" caused a performance regression by dropping the line
which sets mReadUsageCount to 0. This causes markBufferUsage() to clear mResovedData
which then has to be restored on the next getData() call.

BUG=angle:613

Change-Id: I61c4b4960305a69b315c20ced66265a770002338
Reviewed-on: https://chromium-review.googlesource.com/197503
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@chromium.org>
Reviewed-by: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>

ecoal95/angle,mybios/angle,jgcaaprom/android_external_chromium_org_third_party_angle,ecoal95/angle,csa7mdm/angle,ppy/angle,MSOpenTech/angle,xin3liang/platform_external_chromium_org_third_party_angle,bsergean/angle,ecoal95/angle,bsergean/angle,ppy/angle,jgcaaprom/android_external_chromium_org_third_party_angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,mikolalysenko/angle,vvuk/angle,mikolalysenko/angle,ghostoy/angle,mybios/angle,mlfarrell/angle,mlfarrell/angle,crezefire/angle,mrobinson/rust-angle,larsbergstrom/angle,larsbergstrom/angle,mlfarrell/angle,mikolalysenko/angle,mlfarrell/angle,csa7mdm/angle,xin3liang/platform_external_chromium_org_third_party_angle,crezefire/angle,vvuk/angle,MSOpenTech/angle,domokit/waterfall,jgcaaprom/android_external_chromium_org_third_party_angle,nandhanurrevanth/angle,android-ia/platform_external_chromium_org_third_party_angle,xin3liang/platform_external_chromium_org_third_party_angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,csa7mdm/angle,crezefire/angle,bsergean/angle,vvuk/angle,vvuk/angle,mrobinson/rust-angle,domokit/waterfall,android-ia/platform_external_chromium_org_third_party_angle,larsbergstrom/angle,ecoal95/angle,bsergean/angle,mrobinson/rust-angle,ppy/angle,mrobinson/rust-angle,android-ia/platform_external_chromium_org_third_party_angle,MIPS/external-chromium_org-third_party-angle,MIPS/external-chromium_org-third_party-angle,mybios/angle,MIPS/external-chromium_org-third_party-angle,MSOpenTech/angle,jgcaaprom/android_external_chromium_org_third_party_angle,android-ia/platform_external_chromium_org_third_party_angle,ghostoy/angle,csa7mdm/angle,ppy/angle,nandhanurrevanth/angle,MIPS/external-chromium_org-third_party-angle,ghostoy/angle,nandhanurrevanth/angle,MSOpenTech/angle,xin3liang/platform_external_chromium_org_third_party_angle,mikolalysenko/angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,nandhanurrevanth/angle,mybios/angle,mrobinson/rust-angle,ecoal95/angle,larsbergstrom/angle,ghostoy/angle,crezefire/angle