webtry: Only create sqlite3 tables if they don't exist yet.
webtry: Only create sqlite3 tables if they don't exist yet.

Otherwise it will through an error like the following:

2014/09/28 21:22:24 Info: status creating sqlite table for sources:
"table source_images already exists"
2014/09/28 21:22:24 Info: status creating sqlite table for webtry:
"table webtry already exists"
2014/09/28 21:22:24 Info: status creating sqlite table for workspace:
"table workspace already exists"
2014/09/28 21:22:24 Info: status creating sqlite table for workspace
try: "table workspacetry already exists"

To test locally the following was done:

$ ./gyp_skia gyp/webtry.gyp gyp/most.gyp -Dskia_gpu=0
$ ninja -C out/Debug webtry
$ cd experimental/webtry
$ go get -d
$ go build webtry.go
$ ./webtry
$ google-chrome http://localhost:8000

Expected: see no more the above messages.

BUG=None
TEST=see above
R=stephana@google.com, jcgregorio@google.com

Author: tfarina@chromium.org

Review URL: https://codereview.chromium.org/613593002

todotodoo/skia,DiamondLovesYou/skia-sys,todotodoo/skia,TeamExodus/external_skia,timduru/platform-external-skia,BrokenROM/external_skia,geekboxzone/mmallow_external_skia,jtg-gg/skia,rubenvb/skia,MinimalOS-AOSP/platform_external_skia,Hikari-no-Tenshi/android_external_skia,Jichao/skia,UBERMALLOW/external_skia,AOSPB/external_skia,TeamTwisted/external_skia,HalCanary/skia-hc,AOSPB/external_skia,tmpvar/skia.cc,MonkeyZZZZ/platform_external_skia,google/skia,timduru/platform-external-skia,shahrzadmn/skia,MinimalOS-AOSP/platform_external_skia,TeamExodus/external_skia,DiamondLovesYou/skia-sys,tmpvar/skia.cc,vanish87/skia,VRToxin-AOSP/android_external_skia,scroggo/skia,TeamExodus/external_skia,PAC-ROM/android_external_skia,AOSP-YU/platform_external_skia,w3nd1go/android_external_skia,nfxosp/platform_external_skia,w3nd1go/android_external_skia,samuelig/skia,YUPlayGodDev/platform_external_skia,jtg-gg/skia,invisiblek/android_external_skia,vanish87/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,BrokenROM/external_skia,rubenvb/skia,w3nd1go/android_external_skia,PAC-ROM/android_external_skia,shahrzadmn/skia,PAC-ROM/android_external_skia,ominux/skia,TeamExodus/external_skia,AOSPB/external_skia,AOSP-YU/platform_external_skia,chenlian2015/skia_from_google,Igalia/skia,timduru/platform-external-skia,TeamTwisted/external_skia,Jichao/skia,tmpvar/skia.cc,rubenvb/skia,boulzordev/android_external_skia,invisiblek/android_external_skia,Hikari-no-Tenshi/android_external_skia,MinimalOS-AOSP/platform_external_skia,google/skia,ominux/skia,spezi77/android_external_skia,tmpvar/skia.cc,google/skia,aosp-mirror/platform_external_skia,UBERMALLOW/external_skia,HalCanary/skia-hc,HalCanary/skia-hc,noselhq/skia,AOSPB/external_skia,google/skia,HalCanary/skia-hc,nvoron23/skia,shahrzadmn/skia,shahrzadmn/skia,pcwalton/skia,MonkeyZZZZ/platform_external_skia,AOSP-YU/platform_external_skia,tmpvar/skia.cc,AOSP-YU/platform_external_skia,amyvmiwei/skia,MonkeyZZZZ/platform_external_skia,DiamondLovesYou/skia-sys,qrealka/skia-hc,YUPlayGodDev/platform_external_skia,MonkeyZZZZ/platform_external_skia,scroggo/skia,aosp-mirror/platform_external_skia,amyvmiwei/skia,HalCanary/skia-hc,vanish87/skia,TeamTwisted/external_skia,YUPlayGodDev/platform_external_skia,chenlian2015/skia_from_google,nfxosp/platform_external_skia,TeamTwisted/external_skia,aosp-mirror/platform_external_skia,scroggo/skia,timduru/platform-external-skia,pcwalton/skia,jtg-gg/skia,vanish87/skia,scroggo/skia,aosp-mirror/platform_external_skia,MonkeyZZZZ/platform_external_skia,qrealka/skia-hc,vanish87/skia,Hikari-no-Tenshi/android_external_skia,jtg-gg/skia,boulzordev/android_external_skia,amyvmiwei/skia,PAC-ROM/android_external_skia,spezi77/android_external_skia,TeamTwisted/external_skia,todotodoo/skia,UBERMALLOW/external_skia,AOSPB/external_skia,tmpvar/skia.cc,BrokenROM/external_skia,VRToxin-AOSP/android_external_skia,Hikari-no-Tenshi/android_external_skia,BrokenROM/external_skia,jtg-gg/skia,Infinitive-OS/platform_external_skia,AOSP-YU/platform_external_skia,HalCanary/skia-hc,OneRom/external_skia,Igalia/skia,invisiblek/android_external_skia,Igalia/skia,geekboxzone/mmallow_external_skia,ominux/skia,timduru/platform-external-skia,OneRom/external_skia,VRToxin-AOSP/android_external_skia,chenlian2015/skia_from_google,invisiblek/android_external_skia,MarshedOut/android_external_skia,amyvmiwei/skia,MarshedOut/android_external_skia,YUPlayGodDev/platform_external_skia,Jichao/skia,VRToxin-AOSP/android_external_skia,OneRom/external_skia,boulzordev/android_external_skia,Jichao/skia,tmpvar/skia.cc,DiamondLovesYou/skia-sys,ominux/skia,AOSPB/external_skia,shahrzadmn/skia,pcwalton/skia,google/skia,chenlian2015/skia_from_google,scroggo/skia,Igalia/skia,geekboxzone/mmallow_external_skia,noselhq/skia,Infinitive-OS/platform_external_skia,AOSPB/external_skia,amyvmiwei/skia,ominux/skia,MonkeyZZZZ/platform_external_skia,aosp-mirror/platform_external_skia,AOSPB/external_skia,BrokenROM/external_skia,tmpvar/skia.cc,samuelig/skia,timduru/platform-external-skia,nvoron23/skia,nfxosp/platform_external_skia,MinimalOS-AOSP/platform_external_skia,nfxosp/platform_external_skia,pcwalton/skia,noselhq/skia,OneRom/external_skia,qrealka/skia-hc,DiamondLovesYou/skia-sys,invisiblek/android_external_skia,vanish87/skia,MinimalOS-AOSP/platform_external_skia,TeamExodus/external_skia,todotodoo/skia,TeamExodus/external_skia,MarshedOut/android_external_skia,TeamTwisted/external_skia,amyvmiwei/skia,MarshedOut/android_external_skia,BrokenROM/external_skia,MarshedOut/android_external_skia,MarshedOut/android_external_skia,geekboxzone/mmallow_external_skia,samuelig/skia,spezi77/android_external_skia,samuelig/skia,TeamTwisted/external_skia,VRToxin-AOSP/android_external_skia,HalCanary/skia-hc,jtg-gg/skia,nfxosp/platform_external_skia,chenlian2015/skia_from_google,amyvmiwei/skia,UBERMALLOW/external_skia,rubenvb/skia,UBERMALLOW/external_skia,AOSP-YU/platform_external_skia,vanish87/skia,pcwalton/skia,MinimalOS-AOSP/platform_external_skia,HalCanary/skia-h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