Detect Chrome for iOS correctly

Chrome for iOS sends the User-Agent as [described here][1]. This change
fixes the detection of Chrome for iOS by handling it as a special case
under AppleWebKit engine.

This fixes #49.

[1]: https://developer.chrome.com/multidevice/user-agent#chrome_for_ios_user_agent.

all_test.go

@@ -466,6 +466,11 @@ var uastrings = []struct {
 		ua:       "Mozilla/5.0 (Linux; Android 4.2.1; Galaxy Nexus Build/JOP40D) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.166 Mobile Safari/535.19",
 		expected: "Mozilla:5.0 Platform:Linux OS:Android 4.2.1 Browser:Chrome-18.0.1025.166 Engine:AppleWebKit-535.19 Bot:false Mobile:true",
 	},
+	{
+		title:    "Chrome for iOS",
+		ua:       "Mozilla/5.0 (iPhone; CPU iPhone OS 11_3_1 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) CriOS/67.0.3396.87 Mobile/15E302 Safari/604.1",
+		expected: "Mozilla:5.0 Platform:iPhone OS:CPU iPhone OS 11_3_1 like Mac OS X Browser:Chrome-67.0.3396.87 Engine:AppleWebKit-604.1.34 Bot:false Mobile:true",
+	},
 	{
 		title:    "WebkitNoPlatform",
 		ua:       "Mozilla/5.0 (en-us) AppleWebKit/525.13 (KHTML, like Gecko; Google Web Preview) Version/3.1 Safari/525.13",

browser.go

@@ -73,6 +73,8 @@ func (p *UserAgent) detectBrowser(sections []section) {
 						p.browser.Name = "Chrome"
 					} else if sections[sectionIndex].name == "Chromium" {
 						p.browser.Name = "Chromium"
+					} else if sections[sectionIndex].name == "CriOS" {
+						p.browser.Name = "Chrome"
 					} else {
 						p.browser.Name = "Safari"
 					}